5 Achroite 9 Cancrinite 6-8 Feldspar 5 Larimar 8 Peristerite 3 Spinel 5 Actinolite 7 Carnelian 4 Fibrolite 5 Lazulite 8 Petalite 4 Spodumene 8 Adularia (moonstone) 1 Cassiterite 9 Fluorite (fluorspar) 8 Leucite 6 Pezzottaite 3 Staurolite 8 Afghanite 2 Cathaystone 4 Forsterite 3 Leuco garnet (grossular) 4 Phenakite 6 Stichtite (chrysotile) 7 Agate 3 Cat's eye (crysoberyl) 2 Gahnite 8 Limori stone 5 Phosphophyllite 1 Strontium titanate 8 Albite 5 Celestine 3 Gahnospinel 8 Magnesite 9 Plastic 5 Sugilite 3 Alexandrite 2 Cerussite 2-3 Garnet 4 Malachite 8 Pollucite 8 Sunstone 3 Almandine 7 Chalcedony 1 GGG 3 Malaya 7 Prase 7 Swiss lapis (jasper) 8 Amazonite 6 Charoite 8 Glass 3 Mali garnet 7 Prasiolite 3 Taaffeite 7 Amber 4 Chiastolite 8 Goldstone 3 Mandarin (spessartite) 5 Prehnite 3 Tanzanite 5 Amblygonite 4 Chloromelanite (jadeite) 6 Goshenite (beryl) 1 Marcasite (see pyrite) 1 Pyrite 8 Tektite 7 Amethyst 5 Chondrodite 5 Grandidierite 8 Maw-sit-sit 3 Pyrope 8 Thomsonite 8 Ammolite 3 Chrysoberyl 3 Grossular 6 Maxixe 7 Quartz 3 Thulite 7 Ametrine 8 Chrysocolla 9 Hackmanite 2 Melanite (andradite) 9 Reindeer stone 7 Tiger's eye 1 Anatase 7 Chrysoprase 6 Hambergite 5 Melinophane 3 Rhodizite-londonite 2 Titanite 4 Andalusite 6 Chrysotile 9 Haüyne 8 Metajade (limori stone) 6 Rhodochrosite 5 Topaz 6 Andesine 7 Citrine 7 Hawk's eye 7 Milarite 3 Rhodolite 2 Topazolite (andradite) 2 Andradite 4 Clinohumite 6 Heliodor 1 Moissanite 3 Rhodonite 6 Tortoiseshell 2 Anglesite 7 Copal 7 Heliotrope 8 Moldavite (tektite) 7 Rock crystal 5 Tourmaline 6 Antigorite 6-9 Coral 1 Hematite / hematine 5 Montebrasite 5 Rubellite 5 Tremolite 3 Anyolite 6 Cordierite 5 Hemimorphite 8 Moonstone 2 Ruby 3 Triphylite 4 Apatite 2 Corundum 6 Herderite 6 Morganite 1 Rutile 3 Tsavorite 7 Apophyllite 4 Cross stone (chiastolite) 3 Hessonite 7 Morion (smoky quartz) 8 Sanidine 8 Tufa (aragonite) 7 Aqua aura (rock crystal) 3 Cross stone (staurolite) 5 Hexagonite 8 Mother-of-pearl 2 Sapphire 9 Tugtupite 6 Aquamarine 1 Cubic zirconia 4 Hiddenite 7 Mtorolite 3 Sapphirine 5 Turquoise 8 Aragonite 1 Cuprite 5 Howlite 3 Musgravite 7 Sard / sardonyx 9 Ulexit 7-8 Aventurine quartz/feldspar 4 Danburite 3 Hydrogrossular 9 Natrolite 8 Saussurite 8 Unakite 4 Axinite 4 Datolite 9 Hydrophane (opal) 7 Nepheline 7 Scapolite 2 Uvarovite 3 Azurite 2 Demantoid 4 Hypersthene 5 Nephrite 2 Scheelite 6 Variscite 4 Barite 1 Diamond 9 Iceland spar (calcite) 8 Obsidian 5 Schorl 5 Verdelite (tourmaline) 3 Benitoite 3 Diaspore 3 Idocrase 5 Odontolite (see turquoise) 7 Sea opal (mother-of-pearl) 6 Verdite 6 Beryl 4 Diopside 5 Indicolite 4 Olivine 6 Serpentine 3 Vesuvianite 6 Beryllonite 4 Dioptase 6 Iolite 7 Onyx 3 Shattuckite 4 Violane (diopside) 6 Bixbite 3 Disthene 7 Ivory / vegetal ivory 8 Onyx marble (aragonite) 8 Shell 6 Water "sapphire" (iolite) 1 Blende 9 Dolomite 4-5 Jade (jadeite / nephrite) 9 Opal 4 Sillimanite 6 Wernerite 7 Bloodstone (heliotrope) 5 Dravite 7 Jasper 9 Opalite (opal imitation) 4 Sinhalite 3 Willemite 5 Bluespar 4 Dumortierite 8 Javaite (tektite) 8 Orthoclase 9 Slocum stone 6 Williamsite 6 Bowenite 8 Eilat stone (chrysocolla) 4 Jeremejewite 2 Padparadscha 5 Smaragdite (actinolite) 1 Wulfenite 5 Brazilianite 5 Ekanite 4 Jet 2 Painite 5 Smithsonite 5 Wyoming jade (nephrite) 4 Bronzite 6 Emerald 4 Kornerupine 5 Pargasite 9 Sodalite 2 YAG 7 Burmite (amber) 4 Enstatite 4 Kunzite 8 Pearl 6 Spectrolite (labradorite) 1 Zincite 6 Bytownite 3 Epidote 3 Kyanite 5 Pectolite 3 Spessartite 2 Zircon 9 Calcite 4 Euclase 6 Labradorite 3 Periclase 1 Sphalerite 3 Zoisite 3 Californite (vesuvianite) 5 Eudialite 8 Lapis lazuli 4 Peridot 2 Sphene 3 Zultanite COPYRIGHT: Hervé Nicolas Lazzarelli 2002-2008 http://www.gembluechart.com Bluechart or gem blue chart is a new and up-to-date gem identification chart. In the world of gem Identification Instruments and Accessories ,it appears as a "perfect" gemological tool, It contains the distinctive features of some 200 gemstones.Anybody who needs a quick, accurate and definitive gemstone identification: Ideal for  the Gemology student, professional gemmologists, gem dealers, jewellers, and gem collectors.Most complete and practical gem property chart ever published...  Practical orientation with focus on really distinctive characteristics. Common and less common traps are emphasized.In this gem reference chart the colours are widely used to quickly and clearly point out distinctive features such as polariscope reactions, wide ranges, doubling, phenomena, treatments, common and uncommon stones, blinking, etc.Special care has been taken to show colours as close as possible to natural/enhanced colours. Special emphasis on features that help distinguish between natural , treated gems, synthetic and imitation / fake gemstones. Classification is based on refractive index; at the end of the chart you will also find a classification based on specific gravity.In addition, an alphabetical index leads to individual gem characteristics.Handy metal wire ring-bound booklet. It contains 10 double pages and has a format that fits easily everywhere.Common gem denomination.Common gem denomination with a clear distinction between GROUP, SPECIES, SUBSPECIES, and VARIETIES is used.
Common and rare phenomena are indicated in distinctive colours.Colour range is shown as close as possible to natural/enhanced colours. Common and less common colours are included.Colour range is shown as close as possible to natural/enhanced colours. Common and less common colours are included. Refractive index, birefringence and doubling.Classification by refractive index with a clear reading of the range. The wide ranges (rhodochrosite, smithsonite, unakite, etc.) are shown in red.birefringence, birefringence range and blinking are clearly indicated. Possible doubling is shown in red.Crystal system, optic character and sign...Quick colour separation of polariscope reactions and crystal systems. Crystal system, optic character and sign.Specific gravity...Classification by specific gravity with a clear reading of the range.At the end of the chart you will find a table listing gems in order of their specific gravity.Hardness range... Distinctive characteristics / Common inclusionsThe right-hand side pages show many tricks and tips in addition to typical features such as visual characteristics, typical inclusions, distinctive spectrum, filter reactions, ...Focus is on distinctive characteristics. Common and less common traps are pointed out. Jewelery tool, ... / ...differences between natural, synthetic, treated and imitated gemstones are explained as clearly as possible.A practical index with 241 entrees completes the chart and allows for quick reference check.Hervé Nicolas Lazzarelli.Bluechart es una nueva y actualizada carta de la identificacion de la gema. Contiene las caracteristicas distintivas de unas 200 piedras preciosas . Cualquiera que necesita una identificacion rapida, exacta y definitiva de la piedra preciosa: Ideal para los estudiantes de Gemmology, los gemmologists profesionales, los distribuidores de la gema, los joyeros, y los colectores de la gema. La carta mas completa y mas practica de la referencia de la identificacion de la gema publicada siempre Orientacion practica con el foco en caracteristicas realmente distintivas Se acentuan el campo comun y las trampas menos comunes Los colores se utilizan extensamente precisan a rapidamente y claramente caracteristicas distintivas tales como reacciones del polariscopio, amplias gamas, doblando, piedras de los fenomenos, de los tratamientos, comunes e infrecuentes, centelleo, etc. El cuidado especial se ha llevado los colores de la demostracion tan cerca como sea posible a los colores de natural/enhanced enfasis especial en las piedras preciosas de las caracteristicas que ayudan a distinguir entre natural , tratado, sinteticas y de imitacion. La clasificacion se basa en el �ndice de refraccion ; en el extremo de la carta usted tambien encontrar una clasificacion basada en gravedad especifica. Ademes, un indice alfabatico conduce a las caracteresticas individuales de la gema El alambre de metal practico anillo-limita el librete. Contiene 10 paginas dobles y tiene un formato que quepa facilmente por todas partes Bluechart est un nouveau et  jour diagramme d'identification de gemme. Il contient les dispositifs distinctifs d'environ 200 pierres gemmes . Quiconque qui a besoin d'une identification rapide, precise et definitive de pierre gemme: Ideal pour des etudiants de Gemmology, des gemmologists professionnels, des marchands de gemme, des bijoutiers, et des collecteurs de gemme. Le diagramme de reference d'identification de gemme le plus complet et le plus pratique ... Orientation pratique avec caracteristiques vraiment distinctives et les pieges moins communs sont soulignes Des couleurs sont largement utilisee... rapidement et clairement les dispositifs distinctifs tels que des reactions de polariscope, , doubling, pierres de phenomenes, de traitements, communes et rares, ...   Soin special a ete pris aux couleurs d'exposition aussi etroitement que possible aux couleurs de natural/enhanced Consideration particuliere sur les pierres gemmes de dispositifs qui aident a distinguer naturel  , traitee, synthetiques et d'imitation. La classification est basee sur l'indice de refraction ;  l'extremite du diagramme vous trouverez egalement une classification base sur la densite. En outre, un index alphabetique mene a differentes caracteristiques de gemme Le fil maniable en m�tal anneau-bondissent le livret. Bluechart ist ein neues und aktuelles Edelsteinkennzeichnung Diagramm. Es enth�lt die unterscheidenden Eigenschaften von ca. 200 Edelsteinen . Jedes, das eine schnelle, genaue und endg�ltige Edelsteinkennzeichnung ben�tigt: Ideal f�r Gemmology Kursteilnehmer, professionelle gemmologists, Edelsteinh�ndler, Juweliere und Edelsteinsammler. Komplettestes und praktischstes Edelsteinkennzeichnung Bezugsdiagramm �berhaupt ver�ffentlicht Praktische Lagebestimmung mit Fokus auf wirklich unterscheidenden Eigenschaften Common und weniger allgemeine Fallen werden hervorgehoben Farben werden allgemein zu schnell und unterstreichen offenbar unterscheidende Eigenschaften wie Polariskopreaktionen, die breiten Strecken verwendet und verdoppeln, der Behandlungen, allgemeiner und seltener die Steine der Ph�nomene, und blinken, usw.. Besondere Sorgfalt ist zu den Erscheinenfarben so nahe angewendet worden, wie m�glich zu den natural/enhanced Farben Besondere Betonung auf den Eigenschaften, die helfen, zwischen nat�rlichem zu unterscheiden, behandelt, synthetischen und nachgemachten Edelsteinen. Klassifikation basiert auf Brechungsindex ; am Ende des Diagramms finden Sie auch eine Klassifikation basiert auf spezifischem Gewicht. Zus�tzlich f�hrt ein alphabetischer Index zu einzelne Edelsteineigenschaften Handlicher Metalldraht Ring-springen Brosch�re. Er enth�lt 10 doppelte Seiten und hat ein Format, das leicht �berall pa�t Bluechart PYRITE, HEMATITE, CUPRITE, MOISSANITE, RUTILE, DIAMOND, IRRADIATED DIAMOND, SYNTHETIC DIAMOND, STRONTIUM TITANATE, SPHALERITE, WULFENITE, CUBIC ZIRCONIA, G.G.G, CASSITERITE, SCHEELITE, SPHENE, ANDRADITE, DEMANTOID, UVAROVITE, YAG, GAHNITE, CERUSSITE, CATHAYSTONE, ZIRCON, HIGH TYPE ZIRCON, MEDIUM TYPE ZIRCON, LOW TYPE ZIRCON, CORUNDUM, YELLOW, BLUE, ORANGE, GREEN SAPPHIRE, PADPARADSCHA, DIFFUSED PADPARADSCHA, RUBY, HEAT-TREATED CORUNDUM, HEAT-TREATED SAPPHIRE, HEAT-TREATED RUBY, DIFFUSED CORUNDUM, DIFFUSED SAPPHIRE, SYNTHETIC FLAME FUSION,
SYNTHETIC FLUX, SYNTHETIC HYDROTHERMAL, SYNTHETIC SAPPHIRE, SYNTHETIC RUBY, SYNTHETIC CORUNDUM, VERNEUIL RUBY, VERNEUIL SAPPHIRE, FLAME FUSION RUBY, FLAME FUSION CORUNDUM, HYDROTHERMAL RUBY, GARNET, SPESSARTITE, ( SPESSARTINE ), MALAYA, COLOUR - CHANGE, COLOR CHANGE,ALMANDINE, RHODOLITE, PYROPE, GROSSULAR, GROSSULARITE, HESSONITE, TSAVORITE AND IMITATION,GAHNOSPINEL, BENITOITE, SHATTUCKITE, CHRYSOBERYL, CAT'S EYE, ALEXANDRITE, SYNTHETIC CHRYSOBERYL, SYNTHETIC CAT'S EYE, SYNTHETIC ALEXANDRITE, STAUROLITE, EPIDOTE, AZURITE , HYDROGROSSULAR GARNET, SPINEL, SYNTHETIC SPINEL, FLUX SPINEL, TAAFFEITE, RHODONITE, IDOCRASE, KYANITE, WILLEMITE, ZOISITE, TANZANITE, THULITE, DUMORTIERITE, AXINITE, DIOPSIDE, SINHALITE, KORNERUPINE, ENSTATITE, BRONZITE, HYPERSTHENE, JADEITE, JADE, IMPERIAL JADEITE, DYED JADEITE, LAVENDER JADEITE, SILLIMANITE, SPODUMENE, KUNZITE, HIDDENITE, JET, MALACHITE, DIOPTASE, PHENAKITE, EUCLASE, PERIDOT,  SYNTHETIC FORSTERITE, BARITE, APATITE, ANDALUSITE, CHIASTOLITE, DANBURITE, DATOLITE, TOURMALINE, IRRADIATED TOURMALINE, HEAT-TREATED TOURMALINE, ACROITE, PARAIBA , RUBELLITE, DRAVITE, SCHORL, INDICOLITE, CHROME TOURMALINE, SMITHSONITE, ACTINOLITE, ACTINOLITE CAT'S EYE, NEPHRITE, TOPAZ, TOPAZ IMPERIAL, PREHNITE, LAZULITE, TURQUOISE, IMPREGNATED TURQUOISE, RECONSTRUCTED TURQUOISE, SYNTHETIC TURQUOISE, SUGILITE, MONTEBRASITE, AMBLYGONITE, BRAZILIANITE, PECTOLITE, LARIMAR, EKANITE, PHOSPHOPHYLLITE, HOWLITE, VERDITE, RHODOCHROSITE, VARISCITE, BERYL, AQUAMARINE, BIXBITE, MORGANITE, HELIODOR, GOLDEN BERYL, EMERALD, FLUX EMERALD, HYDROTHERMAL EMERALD, SYNTHETIC EMERALD, FRACTURE-FILLED EMERALD, FRACTURE FILLING, FELDSPAR, LABRADORITE, CORAL CONCHIOLIN, IMITATION CORAL, SERPENTINE, BOWENITH, BERYLLONITE, TORTOISESHELL, CHAROITE, QUARTZ CRYSTALLINE, ROCK CRYSTAL, AQUA AURA, AMETHYST, CITRINE, AMETRINE, PRASIOLITE, LEMON ROSE SMOKY QUARTZ, HYDROTHERMAL QUARTZ, QUARTZ MICROCRYSTALLINE, AVENTURINE QUARTZ, PRASE, QUARTZ CAT'S - EYE, TIGER'S - EYE, HAWK'S - EYE, IOLITE, IVORY, VEGETAL IVORY, TAGUA, AMBER, COPAL, AMBROID,   SCAPOLITE, QUARTZ CHALCEDONY, CHRYSOPRASE, MTOROLITE, CARNELIAN, SARD, HELIOTROPE, ONYX, SARDONYX, AGATE, FIRE AGATE, IRIS AGATE, MOSS AGATE, DENDRITIC AGATE, JASPER, APOPHYLLITE, SHELL, MOTHER-OF-PEARL, AMMOLITE, PEARL, CULTURED PEARL, KESHI PEARL, BLISTER PEARL, MABE PEARL, DYED PEARL, IRRADIATED PEARL, IMITATION PEARL, ARAGONITE, UNAKITE, SAUSSURITE, ALBITE, SUNSTONE,  AMAZONITE, ADULARIA, MOONSTONE, ORTHOCLASE NOBLE, MAW-SIT-SIT, POLLUCITE, NATURAL GLASS, GOLDSTONE, LIMORI STONE, OBSIDIAN, SNOWFLAKE, TEKTITE, MAGNESITE, THOMSONITE, LEUCITE, PETALITE, LAPIS LAZULI, DYED LAPIS LAZULI, IMITATION LAPIZ LAZULI, CHRYSOCOLLA, HAUYNE, TUGTUPITE, CALCITE, CORAL CALCIUM CARBONATE, SODALITE, NATROLITE, PLASTIC, CELLULOIDE, BAKELITE, BLACK OPAL, OPAL, COMMON OPAL, PRECIOUS OPAL, FIRE OPAL, MATRIX OPAL, BOULDER OPAL, OPALIZED ORGANIC MATERIALS, SYNTHETIC OPAL, IMITATION OPAL, SLOCUM STONE, FLUORITE, ANGEL'S SKIN, ANTIGORITE, ANYOLITE,  AVENTURINE FELDESPAR, BASALT GLASS, BLENDE, BLOODSTONE, CALIFORNITE, CHLOROMELANITE, CHRYSOTILE, CINNAMON STONE, CROSS STONE, DISTHENE, EILAT STONE, FABULITE, FIBROLITE, GOSHENITE, HEMATINE, KORITE, LEUCO GARNET, MALI GARNET, MANDARIN, MARCASITE, MAXIXE AQUAMARINE, MELANITE, METAJADE, MICROCLINE, MOLDAVITE, MOMO, MORION, MORO, ODONTOLITE, OLIVINE, ONYX MARBLE, OPALITE, OX-BLOOD, REINDEER STONE, SARDEGAN, SEA OPAL, SPECTROLITE, STICHTITE, TITANITE, TOPAZOLITE, TRANSVAAL JADE, TUFA, VERDELITE, VESUVIANITE, VICTORIA STONE, VIOLANE, WATER-SAPPHIRE, WILLIAMSITE, WYOMING JADE, ...  / ... gem identification chart or properties list and table for the easiest gem identification , ..../ ...synthetic  gemstone, imitation and treated gems are easily separeted with this gemstone property table. A - practical orientation, B all the distinctive tips and tricks for gemstone identification, C ...  /  ...  gem chart, blue chart, gembluechart, gemstone identification bluechart, gemchart or gem table are common denominations for this new, complete and up-to date property chart ... / ... practical orientation for a secure gemological diagnostic, ...  /  ...  with this gemmological properties table with focus:  A  on treated gems, B on synthetic gemstones, C on imitation material.  ...   / ... Gem imitation as well as synthetic, assembled doublet, triplet " gemstones " will be easily identifyed, ... /  ... nicolas gem chart, a realy useful tool for gemological classe, school and institute , .../...  are we facing a natural, heat treated gem ?  What kind of treatment are possible for this particular  gemstone ?  Irradiation is for example commonly used to enhance the pink tourmaline... but how can one make the diference between a natural and a irradiated material ? This is not always possible for example in the case of the yellow beryl which ... /  ... a gemmological tool for an easy distinction between most gem material available on the market, ....// ....  gemstone property list in order to get A , the quicker and more accurate identification and B, the most complete reference ... / ...    Streak : Greenish to brownish black  /  Misnamed marcasite, closely related mineral ...SG 4.80 - 4.92, (Orthorhombic).../ ...Imitated by man-made "hematine": Mainly constituted of stainless steel.../...  Gem table : Less transparent than diamonds under UV ; Also Heavy liquid separation: Methylene iodine : SG 3.32... /...Natural rutile occurs in dark yellowish brown, reddish brown to black colour.../ ...  with this gemstone analysis tool ...  / ... Naturals: Bearding, frosted girdle, trigons, crystal inclusions  /  "Cape" diamonds usually show lines in blue spectrum... /  ... with this gemstone property chart, you will learn that the intense yellow diamonds fluoresce yellow and do not show absorption bands...  /  ...common imitations: Cubic Zirconia, Moissanite (May react the same way on old diamond testers) /  May be fracture filled: Orange to purple flash effect seen parallel to fracture, .../...show "umbrella effect" around culet or "ring effect" around girdle...  / ...May be laser drilled to remove black spots: Channel(s) may be seen.../... Irradiated blue diamond doesn't phosphoresce, remains opaque under SW UV, ...  Irradiated black shows a dark greenish tinge in transparency.../... Irradiated diamond spectrum: May show a distinctive narrow line in the yellow at 594 nm (+ lines in green at 504 and 497), with or without "cape" lines.../... Irradiated black shows a dark greenish tinge in transparency...    
...  FABULITE   /  Brittle unlike diamond it imitates, may show rounded facet junctions and polishing lines.../... BLENDE  /  Very strong dispersion  /  Colour zoning  /  Perfect cleavage: 6 directions  /  Common inclusions: Dark brassy yellow chalcopyrite.../...Strong doubling of back facet junctions  /  Brittle ... / ...May show misleading feathers-like inclusions).../...,  May show colour banding  /  (Fluid inclusions, greenish transparent needles of tourmaline,.../...TITANITE   /  Common inclusions of actinolite needles.../...Yellow variety: TOPAZOLITE: See grossular page 2  /  Black variety: MELANITE  /  Reddish brown variety may show chatoyancy.../...red-end at 701 nm (Chromium spectrum); Weak to strong red reaction through chelsea filter.../ ...Byssolite: "Horsetails" ... /  Spectrum characterized by an absorption band in the blue (+/- 445 nm); .../ ...May show misleading flux inclusions: Feathers, linear arrangement of tiny grains...  /  Green garnets imitation: Red through chelsea filter (Chromium), .../...Usually too dark to be faceted  /  See gahnospinel page 2  /  (Synthetic : RI: 1805,  SG: 4.40)  Spinel group.../... Sharp cat's eye  /  Fiberoptic glass: Fibres are stacked in hexagonal or cubic.../... Abraded facet junctions, (brittleness increasing with heat-treatment) /... May show a typical "jailhouse" spectrum.../... Blue, golden, colourless zircons are commonly produced by heat-treatment of a reddish brown variety: Blue colour may fade.../ ... Metamisation: Disintegration of the high type crystal structure up to the almost isotropic low type  /... /  gem stone... .  /  Low type: Repeated twining and - or zoning, .../
... sapphire  typical inclusions: "Fingerprint" or "fly's wing-like" inclusions  /  Rutile needles  (also ilmenite) usually as "silk" intersecting at 60°-120°, crystals of apatite, calcite, dolomite,... /  Straight or angular colour zoning  /... Colourless sapphire fluorescence: Commonly weak to moderate orangy red under SW, .../ ...Yellow and padparadscha sapphire may result from irradiation (Colourless to light yellow can turn into yellow, pink into padparadscha): Colour often unstable, fading with ... 
 ...Distinctive inclusion: "Silk": ... /  ... may be glass filled: Distinct surface luster (Gas bubbles may be seen)  /  ... if dyed: Colour concentration may be seen in cracks and .../... very common  /  Melted crystals: Rounded, may have snowball appearance; Commonly surrounded by discoid fractures (Tension cracks)  /  Partially disolved "silk"  (Dot-like).../...flux remnants.../ ... in blue sapphire from madagascar... / ... which is the case in surface reaching cracks (ruby) /  May fluoresce chalky green under SW, (blue sapphire, padparadscha, ...  
... from the culet with diffused transmitted light: Colour concentration at facet junctions, in cracks, around girdle, uneven facet to facet colour distribution.../ ... Colourless sapphire fluorescence: Commonly weak to moderate orangy red under SW, .../... in ruby from Burma ( Myanmar )Yellow and padparadscha sapphire may result from irradiation (Colourless to light yellow can turn into yellow, pink into padparadscha): Colour often unstable, fading with .../ ...Distinctive inclusion: "Silk": ... /  ... may be glass filled: Distinct surface luster (Gas bubbles may be seen)  /  ... if dyed: Colour concentration may be seen in cracks and.../... very common  /  Melted crystals: Rounded, may have snowball appearance; Commonly surrounded by discoid fractures (Tension cracks)  /  Partially disolved "silk"  (Dot-like)...    flux remnants
 ... in surface reaching cracks (ruby) /  May fluoresce chalky green under SW, (blue sapphire, padparadscha, .../ ... diffused star: Very thin fabric structure: Shallow fuzzy whitish surface layer under fiber-optic light. Unlike natural, the rays may not be... / ...(hexagonal) colour banding.../ ... curved growth lines and colour banding  (Diffused light), gas bubbles  /  Boehmite needles, cracks (and "feathers" !)  may be induced  (Ruby).../... unlike most of unheated natural  /  Colourless commonly weak bluish white under SW UV .../... white to orangy flux inclusions often in misleading "fingerprint" pattern, especially in the case of rubies : .../... hexagonal and triangular platinum platelets.../... (Manganese aluminium silicate)  /  "Fingerprint" inclusions, rutile needles... / ... variety: MANDARIN.../... pyrope-spessartite garnet commonly mixed in lower proportion with almandine and grossular garnet...  /  Spectrum: .../...  in addition to malaya spectrum a broad absorption band in the yellow .../... difference between these 3 garnets depends on the iron and magnesium proportion: Iron = almandine, magnesium = pyrope. The intermediate garnets, +/-  1.745 -1.765, are called.../... hydrogrossular  /  MALI GARNET: Yellow to greenish brown variety mixed with andradite garnet  (+/-20%, page 1): Commonly shows RI of +/-1.772, SG of +/-3.68  /  Colourless variety: LEUCO GARNET.../... ( CINNAMON STONE )  /  Magnification: Characteristic "heat-wave" effect, oily appearance  /  Rounded crystal of apatite, calcite, zircon  /  Inert under .../... "feathers" of tiny negative crystals, fluid inclusions, ... /  Chelsea filter: May react pinkish to red, depending on chromium content  /  Common imitation: YAG  page .../... clouds of tiny needle-like rutile inclusions; Actinolite, goethite needles, liquid fingerprint, 2 phase inclusions  /  Yellow, green and brown: Typical spectrum: Absorption band in .../...Transition between gahnite and spinel.../... Strong pleochroism: Blue - colourless... /  Common inclusions of tiny white crossite fibers.../... used as amulets: "CROSS STONE" :See chiastolite p. 4 /  Transparent dark brown crystals have been cut; Spectrum: Strong line in the blue (450 nm).../... Epidote group and species, .../... imitations: C-C garnet, synthetic spinel & sapphire, C-C tourmaline (p.4), .../... may intergrow with malachite  (page 3): AZURMALACHITE, .../... translucent to opaque massive grossular garnet:  Inclusions: Black specks of magnetite  /  Often miscalled  "transvaal jade"  /  Pink variety: RI and SG on ... /... may intergrow with idocrase and.../... parallel rows of tiny spinel octahedrons or dolomite rhombohedrons. / Gemological Instruments .... / ...  Blue: Rarely coloured by cobalt: Pinkish through chelsea filter, .../ ... blue: Pinkish through chelsea filter: Imitates aquamarine, sapphire, .../... : Pinkish to red reaction due to Cobalt: Typical spectrum: 3 broad bands; One centered in the orange, one in the yellow and one in the green.../... "True" cat's eye due to numerous minute tubular cavities or acicular crystals parallel to optical axis  /  Inert under SW and LW  /  Imitated by quartz cat's eye (page 6), man-made glass (limori stone page 7), .../..., ( VESUVIANITE )  /  CALIFORNITE: Translucent to opaque yellow green variety; Typical spectrum: 1 line in the blue, 1 weaker in the green (464, 528 nm) /.../... , ( DISTHENE )  /  One perfect cleavage; Low hardness parallel to crystal length, high at 90°  /  Strong pleochroism  /  Spectrum: 2 lines in the blue (435, 445 nm)  /  May fluoresce reddish (LW)  /.../..., common ornamental: Massive green with black spots and opaque ruby inclusions ( ANYOLITE )  /  (Epidote group) 
 ... , strong pleochroism: Blue - greenish yellow - purplish red  /  Commonly imitated by synthetic forsterite  (See below)  /  Colour commonly improved by heat-treatment .../..., commonly intergrowned with quartz p.6  (RI: +/-1.540: DUMORTIERITE QUARTZ)  /  Rare in crystal form: Strong pleochroism .../  VIOLANE: Violet-blue variety  /  CHROME DIOPSIDE: Emerald green: Chelsea filter: Reddish to .../ ...493 nm)  /  Inclusions of parallel sillimanite needles. / .../..., hypersthene commonly showing reddish aventurescence due to platy inclusions of hematite and goethite. / .../... : bronzite: Brown body with fibrous inclusions: Bronzelike submetallic luster  /  The relative difference between these three stones depends on the iron and magnesium proportion: RI and SG increasing with iron content. /  ... : typical spectrum: One strong and one weak line in the green (505, 550 nm) (505 line may also be seen in diopside: See above)  /  Black star: Fuzzy rays; Bronze colour sheen, .../... , dyed in any colour. /  CHLOROMELANITE: Black veined and spoted variety: See maw-sit-sit p.7  /  See nephrite p.4  /  Common imitations: Chalcedony p.6, bowenite p.5,californite: See idocrase above, hydrogrossular p.2, saussurite p.7, limori stone p.7, .../... ( FIBROLITE ): Usually cat's eye due to perpendicular greyish hypersthene fibres and parallel arrangement of rutile needles  (Commonly greyish brown to dark brown)... /... , along cleavage planes: Perfect prismatic cleavage  (2 directions: +/- 90°)  /  The colour may fade when exposed to sunlight   /  Commonly irradiated to improve the colour or change the kunzite to the rare hiddenite variety (Colour unstable).../ ... emerald green hiddenite showing chromium lines in the red  (690, 686, 669, 646 nm), and a broad absorption band in the yellow orange (+/- 620 nm); Two lines in the blue may also be seen  (437, 433 nm), .../ ... tests  (SG: 3.90 - 4.00)  /  May intergrow with azurite (page 2): AZURMALACHITE, ...  /  in the case of a gem tool ... / ... peridot : Doubling  /  Magnesium iron silicate: Iron spectrum: Three bands in the blue-green  (453, 477, 497 nm)  /  Disk-like inclusions ("Lily pad"), chromite octahedrons, ... /  ... Olivine group, .../... , small needle-like inclusions, striations  /  Common imitation of tanzanite  /  (Natural forsterite not gem quality)  /  Synthetic Olivine: See remark 1. /... /...  /  Sometime called "CROSS STONE": (See staurolite p.2).  /  ... copper content, commonly after heat-treatment  /  (May be fractured-filled: See emerald p.5)   ... all brownish to yellowish brown tourmalines tend to be called dravite, belonging or not to the species. / ... /  ...green tourmaline  ( VERDELITE ) often shows indicolite spectrum  (Also commonly heat-treated)  /  CHROME TOURMALINE: Fine chrome-rich emerald colour: Reddish through chelsea filter...  /   ... perfect cleavage: Two directions  /  The fibrous aggregate differs from nephrite by its greater iron content (More than 5%). ... /... fibrous  /  Commonly high dome cut  /  Sometime called "cat's eye jade", ... /   ...  /  Black inclusions common  /  ( WYOMING JADE: Rich apple-green variety )  /  Less commonly dyed than jadeite because of its more compact structure, may be impregnated:  See jadeite page 3, ...   /  ...  topaz ./  Irradiation followed by heat-treatment routinely produce blue colour  (Light blue also natural), Strong green results from diffusion process /  Pink and purplish pink commonly produced by heat-treatment of the sherry brown variety: .../.../  ...turquoise.  May have black "spiderweb" matrix  /  Chelsea filter: No reaction unlike some imitations like variscite (page 5), dyed howlite  (page 5), dyed magnesite (page 7), etc.  /  Usually opaque to semi-translucent under... 
   ... strong transmitted light  /  Inclusions of pyrite, quartz, etc  /  Often dyed: Acetone may reveal the dye: Depending on coating  /  Odontolite, fossil tooth or bone, has been used as imitation: "FOSSIL TURQUOISE" :RI: 1.600  (1.570 - 1.630),   SG: ... / ...("Fish-eggs"; "Cream-of-weat") not seen in natural turquoise  /  Usually translucent under strong transmitted light ,... / ... ( AMBLYGONITE BI - )  /  Commonly light yellow  /  Perfect basal cleavage  /  May fluoresce light green to LW UV or phosphoresce light blue to both LW and SW UV, ... / ... luster  /  Sometime used as jade simulant  /  Fluorescence: Common orange to yellow glow under UV light, ... / ... have black "spiderweb" matrix  /  Dyed blue to imitate turquoise (and lapiz): Chelsea filter: Pink to red reaction; Spectrum: One band in the red and one in the yellow green, .../ ... spots  /  Mainly constituted of chromium-rich mica fuchsite  (Lines in the deep red spectrum, commonly 3, may be seen)./  ..., 650 nm)  /  Chelsea filter: Pinkish to reddish reaction unlike turquoise it imitates. / .../ ... , tube-like inclusions parallel to optical axis  /  Common pleochroism: Colourless to greenish bluish - blue green to sky blue  /  Chelsea filter: Greenish bluish; Synthetic spinel and quartz appear pinkish to red (Cobalt); .../ ... blue Topaz appears greyish to blue without greenish through the filter; In addition, it may show a colourless, pinkish, bluish pleochroism  / .../... /  Often produced by irradiation of goshenite (Commonly not detectable)  /  May show planes of tiny two phase inclusions  /  Pure yellow also called GOLDEN BERYL, .../ ...  absorption band in the red spectrum  /  Doublets and triplets used to be common: See remark 2  /  TRAPICHE colombian emerald: Six green arms extending from central green core; white impure.../ ... typical 3 phase inclusions (Sometimes jagged), albite, pyrite, calcite crystals  /... 
  ... spectrum: See above: Coated beryl, ... / ... phenakite crystals with or without extending 2 phase inclusions "Nailhead spicules"  /  Small veils of minute liquid inclusions  /  Cellular pattern (Lechleitner)  /  Hexagonal and triangular platinum platelets  / See remark 1 / ... AIMERALDA )  /  Many kinds: Mainly made of glass, may contain beryl powder  /  Veil-like inclusions, gas bubbles  /  May be ADR* or show anomalous "aggregate" reaction  /  See remark 1 / .../ ... blue to green labradorescence: With all spectral colours: SPECTROLITE  /  Repeated twinning  /  Transparent stones: Common small elongated black inclusions (Ilmenite)  /  See moonstone page 7, .../... may be bleached to create the rare lighter "golden" colour: SG on the low side  /  See: Coral calcium carbonate page 8, ... 
   ... commonly red and pink  /  High magnification: Grainy structure  /  See: Coral calcium carbonate page 8  / .../ ... CHRYSOTILE: Mottled, veined variety; Common yellow veins on dark green body colour  /  ANTIGORITE: Massive, platy variety  /  Intense oily green variety called WILLIAMSITE: Typical inclusions of dark octahedral ... / ... STICHTITE: Pink red to purple variety, ... / ...Shell of hawksbill  turtle (Endangered species). Magnification: Colour made of small spherical dot-like patches concentrated in dark areas, unlike the very common plastic imitation p.8,... /  ...translucent to opaque violet with white to black swirls, flame-like inclusions: The "charoite" used in the market is a rock composed of various minerals  (Charoite, feldspar, augite, ... / ... /  IRIS, RAINBOW quartz: Iridescence due to natural or induced cracks  /  Doublet and triplet used to be common: Emerald imitation, .../ ...,amethyst and citrine.  / ... "Zebra stripe" inclusions, 2 phase inclusions in veil-like pattern, .../ ... usually produced by heat-treatment of smoky amethyst  /  Commonly sold as yellow topaz  /  Translucent: Chatoyancy & Star ... / ...figure is missing  (Bull's eye): Common in synthetic quartz: See below. 
       If twinned:    The black cross center may show a spiral pattern. /... colour produced by heat-treatment of light amethyst; .../ 2 phase inclusions, dark red hematite inclusions, golden yellow rutile 
   ...very dark stones called MORION  /  May be produced by irradiation of rock crystal, ...  /      needles, ("Venus hair"), black tourmaline crystals, fibers of green actinolite, ...  / ...very dark stones called MORION  /  May be produced by irradiation of rock crystal, ... /... aventurescence caused by platy inclusions of mica  (Green fuchsite)  /  Imitated by "goldstone":  See page 7  /  See feldspar sunstone page 7 / .../ ... may closely resemble chrysoberyl cat's eye  (page 2)   /  (May be dyed: May show colour concentration at fiber's ends), .../ ... the original mineral of the veins is crocidolite: Blue variety of asbestos which advanced decomposition into silica produce the tiger's eye variety, .../ ... , ( CORDIERITE ) (Improperly called "water sapphire")  /  Very strong pleochroism  /  Typical inclusions: Platelets of magnetite, Tabular brownish red iron oxide inclusions: May show glittery effect: BLOODSHOT IOLITE, ... /   ... elephant ivory  (Endangered species): Intersecting structural lines (Lozenge pattern): "Engine-turned" effect  /  High magnification: Undulating fibrils structure, bone imitations showing small dark lines  / ... 
   ... tagua nut  /  Magnification: Parallel elongated cells  /  (Shows a weaker fluorescence than elephant ivory), ... / ... key separation: 1 - Salt saturated water :  Only float amber, copal, polystyrene   2 - One drop of acetone will soften the copal in few seconds: Becomes .../... sticky unlike "true" amber, and disolve the polystyrene  / .../ ...small amber pieces warmed and compressed together  (Reconstructed)  /  Immersion in alcohol reveals hazy outline and different hue of individual pieces, elongated and flattened gas bubbles, .../ ...  the red: 645, 670, 705 nm: Similar to undyed Jadeite (p.3) /  Transmitted light: Dye may show a mosaic-like marking, ... / ... sard is darker than carnelian (Dark reddish brown to brown)  /  Commonly dyed .../ ... ONYX: Straight colour bands (Black base and white upper layer)  /  Black chalcedony  ("Black onyx") is assumed to be dyed  /  SARDONYX: Straight white band of onyx with brownish red band of sard, .../ ... with the exception of moss, dendritic, scenic "agate" which should rather be named moss chalcedony, dendritic chalcedony, etc.  /  Routinely dyed .../ ... FIRE AGATE: Iridescence caused by layers of platy iron oxide crystals: Botryoidal structure, brown body colour  /  IRIS, RAINBOW AGATE : diffraction of light due to bands of transparent fibers closely spaced .../ ... dyed blue to imitate lapis lazuli (page 8): "SWISS LAPIS" (Lacks pyrite inclusion), .../... banded structure /  Often dyed: Acetone test  / Commonly used for carving cameos: White and brown helmet shell and white, orange and pink conch shell: Common flame-like surface.../ …/  Abalone shell strongly iridescent: Paua variety from New Zealand exibit a strong blue - green orient: SEA OPAL, .../... ( KORITE )  /  Fossilized shell of ammonites in the form of aragonite: Thin and fragile lamellar structure in a mosaic-like pattern with opalescent play-of-colour: .../ ... imitations and nacreless pearls  /  Routinely bleached to lighten the dark spots of conchiolin, .../...  conch pearl are non-nacreous (Calcareous concretion) and show a white, orange or pink colour; SG between 2.81 - 2.87; Most of them show a porcelain-like surface with typical flame-like marking .../ ... natural byproduct of the insertion of a cultured pearl's nucleus .../ ... , and black, typically AKOYA PEARLS (Common size 3 to 9 mm)  /  Even colour distribution  /  Colour concentration may be visible around the drill hole (Magnification)  / ... iIrradiation of bleached pearls to produce "black" pearls  /  Magnification: Typical black nucleus and whitish nacre: Separation may be seen in the drill hole .../ ... made of fish scales (Guanine crystals): Magnification: No overlaping structure; .../ ...  spot reading : pink areas  +/- 1.525  (Feldspar), white to gray areas  +/- 1.540  (Quartz), green areas  +/- 1.760 (Epidote) .../ ... . Alteration product of feldspar mainly constituted of zoisite: Green areas  +/- 1.700 and albite: White areas  +/- 1.525  /  Used as jade substitute .../... common blue sheen: See below : moonstone, see page 5: labradorite  /  2 cleavages at nearly 90°, one good, one perfect .../... aventurescence due to platy crystals of hematite and - or goethite: AVENTURINE  /  Imitation: Goldstone: See below  /  See page 6: Aventurine quartz  /  (Feldspar oligoclase), .../  ... ( ADULARIA )  /  White to blue sheen  /  "Centipede" inclusions  /  (Feldspar orthoclase)  /  See above: Albite, ... ,  Imitated by: Adularescent synthetic spinel: SR ADR*, commonly showing a .../... aventurine feldspar (above) and quartz (p.6) imitation  /  Hexagonal or triangular copper platelets reflecting light.../ ... partally devitrified glass looking like nephrite: Jadeite imitation (Metajade); Magnification: Fern-like pattern  /  Imitation of chrysoberyl cat's eye  (Victoria stone) /  See remark 1 / .../ ... varieties according to source: MOLDAVITE, JAVAITE, etc  /  Torpedo shaped gas bubbles  /  Undulating structure with snake-like pattern  /  Polariscope: Common spots of light caused by crystalline particles, ...  / ...common imitation of turquoise, lapis, coral, etc: Chelsea filter: Common reddish reaction; Common white to blue green fluorescence... / ...in the market is mixed with chalcedony p. 6  /  May also intergrow with malachite and turquoise: EILAT STONE: SG up to 3.25.  /   ... ( REINDEER stone )  /  Common white to black mottling  /  May contain black needles or yellow spots  /  Fluoresces salmon red to SW, orange to LW  /  Colour fades temporarily in darkness , .../ ... perfect and easy rhombohedral cleavages (3 directions at 74°)  /  Strongly double refractive /  ICELAND SPAR: Transparent colourless variety  /  Massive variety commonly dyed: Acetone test; Dyed green to imitate .../ ... such as  ANGEL'S SKIN: Pink,  MOMO: Light salmon red,  SARDEGAN: Medium red,  OX-BLOOD, MORO: Red, etc  /  See: Coral conchiolin and imitation page 5, ... /  ... black opal) / ... /   HARLEQUIN OPAL: Mosaic square-like colour pattern,  CRYSTAL OPAL: Transparent to semi-transparent colourless body with strong play-of-colour, .../ ... ( MEXICAN OPAL )  /  If synthetic, common RI: +/- 1.410,  SG: +/- 1.91, common denditric inclusions, commonly fluoresce weak to strong bluish white under UV  (Natural may fluoresce weak orange)  /  See remark 1.  /  ... such as "OPALITE": Convincing translucent milky white with play-of-colour  /  Magnification: May show spheroid, columnar structure or painted-like patches of colour  /  See remark 1  / ... fluorescence: Opalite commonly shows a strong bluish white reaction under LW and a chalky whitish blue reaction under SW;  Natural white opal may fluoresce white to light blue, yellow, green under LW and SW, ... / ... ( FLUORSPAR )  /  Common parallel colour zoning  /  2-3 phase inclusions  /  Perfect and easy octahedral cleavages  /  Fluorescence: Common: Green to blue, especially under LW  /  Colour-change: Blue (Daylight) -.../ ...lavender (Incandescent light)  /  BLUE JOHN variety: Curved bands of blue, violet, dark purple  /  Blue often improved by heat-treatment  /  (Synthetic has been made; RI up to 1.440: Colourless, red, blue, green, ...  /  ... . The canadian Gemmologist, Canadian gemmological association    Toronto.  Boletin del Instituto Gemològico Español    Madrid.  Gems and Gemology,  Gemological Institute of America    Carlsbad, USA .
JewelSiam,  Gem and Jewelry magazin    Bangkok, Thailand. Journal of Gemmology,  Gemmological Institute of Great Britain  London. La gemmologia,  Instituto Gemmologico Italiano    Milan. Revue de Gemmologie,  Association Francaise de Gemmologie    Paris.  The Australian Gemmologist,  Gemmological Association of Australia    Victoria. Zeitschrift der Deutschen Gemmologischen Gesellschaft    Idar-Oberstein..../... Gemological Links. Gems and Precious Stones from ... / ...gemological publication, Gemological Labs, Gemological Organizations and laboratory and services for professional Institutes, Labs and Associations.
education and training programs gem and jewelery tools and equipment, precious and semi-precious gem stones identification with a practical gem property chart .... mineral identification tools, Mohs' hardness points, specific gravity testers, UV lights, diamond testers mineral identification tools and equipment, mineral ID kits, precious stones testers, gem identification tools and equipment, gemstones testers specific gravity tester, specific gravity of minerals, specific gravity of gems, density, jolly balance, mineral hydrometer, electronic scales, electronic balances gems Instruments, refractometers, gem refractometers, Chelsea filter, aqua filter, ruby filter, emerald filter gemstone and mineral guides, gem and mineral books, mineral handbooks http://www.prettyrock.com/php/gem-instruments.htm gemmology, gemology, refractometer, polariscope, darkfield loupe, carat scales, gem scales, tweezers, dichroscope, tools, gem tools gem tools gems - carat scales, gem handling equipment (tweezers, digital calipers and basic gemmology equipment. refractive index, refractive index of minerals, refractive index of gemstones, refractive index of gems, double refraction, anisotropic, birefringence, reflective qualities of gems Gem Enhancement Awareness It is important for the consumer to be aware of the fact that many varieties of gemstones on the market today have been treated or "enhanced" in order to improve their appearance. Additionally, there is a constant battle between unscrupulous gem traders and testing laboratories to hide and detect new treatments. consumers should always require disclosure of any alterations or enhancements of a gemstone before making a purchase. This is especially important if the enhancement to the treated stone is not permanent or if the treated stone will require special care. The Federal Trade Commission (FTC) publishes guidelines for the jewelry trade, stating that consumers must be informed of any gemstone treatments that are not permanent OR that "significantly affects" the value. Most comprehensive gemological reports identify treatment types, and when purchasing a large, expensive stone it is advisable to have a full GIA or AGS report done. Gem Enhancement Classifications The designation for identifying enhancements on a gemological report is: "N" (not enhanced), "E" (normally enhanced), and "T" (nontraditional enhancements). Commonly used methods of enhancement are: Semi-Permanent or Temporary Gem Enhancements Bleaching (B): Used to lighten and/or whiten gemstones or pearls Coating (C): Surface enhancement by enameling, inking, foiling, lacquering, sputtering, or vapor deposition Dyeing (D): Used to enhance the color and uniformity of gemstones or pearls Filling (F): Filling surface cavities or fissures with colorless glass, plastic or resin Impregnation (I): Treating gems with oil, wax, or resin to improve clarity & appearance Waxing (W): Impregnation with colorless wax, paraffin or oil Permanent Gem Enhancements Flux Healing (FH): Heat enhancement used to heal fissures and fractures Fracture Filling (F): Injecting plastics or glass into fractures Heat Treatment (H): Used to lighten, darken, or alter color Irradiation (R): Used to add color intensity to diamonds, gemstones, or pearls Lattice Diffusion (U): High-temperature heat treatment to produce color and/or asterism Lasering (L): Laser and chemical treatment to remove inclusions Most of the 'temporary' enhancements or treatments are basic and self-explanatory, but most of the 'permanent' gem enhancements involve highly sophisticated techniques that can be difficult to detect. Most treatments leave some kind of telltale signature or fingerprint, but as treatment methods become increasingly subtle, they are more problematic. Some of the more involved treatments and enhancements are listed below. These treatments are permanent, but can have a significant impact on the value of a gem. Flux Healing Flux healing involves the filling of surface cracks, cavities, and/or inclusions by exposing the crystal to a combination of heat and borax or other fluxes and solvents to fill voids with molten low-viscosity flux glass. As the flux mixture fills a fracture via capillary action, the molten mixture dissolves the walls of the fracture until the liquid in the crack becomes saturated with the actual mineral's molten solution. Heat Treatment Heat treatment or 'annealing' is done using a combination of chemicals (beryllium, borax, lead, tantalum) and heat to permanently alter a stone's color. Heating or "cooking" the stone is done at temperatures ranging from 450º to 1850º Celsius for a period of 2 to 12 hours or more. One telltale sign of heat-treatment is the presence of small fractures or "decrepitation feather" within the stone that appear around natural mineral inclusions. High-Temperature High-Pressure (HTHP) High-Temperature (2,000º C) High-Pressure (70,000 atmospheres) treatment or HTHP was developed by General Electric in 1999, to lighten or totally remove a brownish hue in some Type IIa diamonds. Type I diamonds have nitrogen impurities that absorbing some of the blue light spectrum, thereby making the diamond appear yellow, while Type II diamonds have structural defects (aka plastic deformations) created during crystal growth, that can cause a brownish color. High-Temperature High-Pressure treatment can in some cases 'repair' these deformations, whitening the diamond's appearance. Type I diamonds which have nitrogen impurities can also have their color altered using High-Temperature High-Pressure treatment. Using HTHP, a company called Nova Diamond creates fancy colors in vivid hues of yellow and green, bypassing the need for irradiation. Diamonds treated by General Electric (Pegasus Overseas Ltd) to remove coloration have the logo "GE POL" laser-inscribed on the girdle, but laser-inscriptions can be removed by polishing. Detection of non-inscribed HTHP treated diamonds is accomplished by gemological testing laboratories using photoluminescence spectroscopy, 'Fourier Transform Spectroscopy' (FTIR) and 'Raman Spectroscopy' to analyze visible and infrared light absorption looking for telltale absorption lines that would indicate high temperature exposure. Additionally, telltale fingerprints that can be seen under a microscope may include dark cracks around inclusions, internal graining, haze, and partially healed feathers. Irradiation Irradiation treatments involve exposing the stone to electromagnetic rays (ionizing radiation) or gamma rays (cobalt 60 radiation) to release electrons from their normal location, moving them to more desirable color-producing locations. Depending on the mineral to be treated, and the desired color alteration, alpha particles, beta particles, electrons, gamma particles, neutrons will be used in the irradiation process. Irradiation treatment uses a linear accelerator to expose the stone to high-energy electrons, a cyclotron for charged high-energy particles such as protons, or an electron-beam nuclear reactor to expose the stone to high energy neutrons. Neutron bombardment and electron bombardment are the two main irradiation methods practiced today. Residual radioactivity in the stone can be a potential concern. The use of a nuclear reactor can create radioactive isotopes in the stone, necessitating storage for a sufficient amount of time for the decay of any residual radioactivity. Lasering & Laser Drilling The laser-drilling of diamonds to reduce or remove foreign crystal inclusions, or iron-oxide stained fractures, has been preformed for over 20 years. Drilling is accomplished using an infrared laser to bore microscopic holes (0.005" diameter) into a diamond, creating an access channel to the inclusion. The diamond is then immersed into a sulfuric acid solution to dissolve any non-diamond crystals and/or staining. The laser-drilling process is followed by glass in-filling to hide the channel, using a glass material with a refractive index that approximates diamond. Several inclusions can be removed from the same diamond using this technique. Visible signs of laser-drilling and subsequent glass-filling can easily be detected under a microscope, and may include semi-opaque white lines that are straight or slightly wavy in appearance, air bubbles and/or flow-lines within the glass-filled hole, and dark circles where the holes breach the diamond's surface. Lattice Diffusion Lattice diffusion is a treatment process using a combination heat and chemicals to 'diffuse' or deposit an element (beryllium, chromium, vanadium, etc.) from an external source into a gemstone in order to alter or improve its color hue or saturation. This treatment is used primarily on corundum (rubies and sapphires) and is considered an unethical practice. Diffusion is a mechanical process where atoms and/or ions move through solid matter. Within a crystal's lattice structure there are missing atoms called "vacancies" that can be filled with a new element's atoms, thereby changing the chemical composition and color of the mineral. Lattice diffusion can be difficult to detect, and therefor, is considered an unethical practice. The diffusion treatment of ruby and sapphire in-particular is major concern within the gem trade. Gemstones & Their Treatment Types Most gemstones, with the notable exception of garnet, have a particular treatment, or series of treatments that are commonly used to increase the marketability of the stone. This list represents common gemstones and the typical treatments they receive. Alexandrite: None Amethyst: Heat Treatment Aquamarine: Heat Treatment Coral: Dyeing Druzy Quartz: Dyeing, Heat Treatment, Irradiation, Vapor Deposition Citrine: Heat Treatment Diamond: Irradiation, Lasering Emerald: Filling, Impregnation, Waxing/Oiling Garnet: None Lapis Lazuli: Dyeing Onyx: Dyeing Opal: Filling, Impregnation, Waxing/Oiling Morganite: Irradiation Pearls: Bleaching, Dyeing, Irradiation Peridot: Impregnation, Waxing Rubelite: Heat Treatment Ruby: Heat Treatment, Flux healing, Fracture Filling Sapphire: Heat Treatment, Flux healing, , Fracture Filling, Lattice Diffusion Spinel: None Tanzanite: Heat Treatment Topaz: Heat Treatment, Irradiation Tourmaline: Heat Treatment, Irradiation Zircon: Heat Treatment Conclusion There is nothing intrinsically wrong with gem enhancements as long as you are made aware of their use. New treatments are being developed all the time, and gemological testing centers are constantly revising and updating their testing regimes to combat the unidentified enhancement that can slip through the cracks. As consumers, we must rely on the testing laboratory's ability to identify enhancements so that a gem's value can be properly ascertained before a purchase is made. Gemological Testing Equipment lattice diffusion, laser drilling, irradiation, high-temperature, high-pressure (HTHP), heat treatment, flux healing, fracture filling, permanent gem enhancements, waxing, impregnation, filling, dyeing, coating, bleaching, permanent or temporary gemstone enhancements

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