General Information |
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Chemical Formula | Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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Photos of natural/un-cut material from mindat.org |
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Turquoise Treatments |
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Commonly impregnated with wax to enchance color or plastic to increase durability: SG on low side, hot pont test, scratch test. May be dyed: color concentration along fractures. Acetone may reveal the dye if not coated. Zachery treatment tests limited. Porosity reduced: doesn't absorb liquids unlike most untreated natural stones, doesn't "discolor" in water. High quality polish. Even (strong) coloration, color concentration diffused along fractures - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5 |
Turquoise Simulants |
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Dyed howlite, dyed magnesite, variscite - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5
Glass can be used as imitation, but it can be identified by the luster of the small fractures on these pieces of opaque blue glass. - GIA, 2018 |
Synthetic Turquoise |
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Synthetic magnification: granular structure - "fish-eggs", "cream-of-wheat". May show black "spiderweb matrix" (rounded pattern). Strong transmitted light: usually translucent - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5 |
Physical Properties of Turquoise |
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Mohs Hardness | 5 to 6Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
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Specific Gravity | 2.30 to 2.90Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
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Cleavage Quality | NoneWalter Schumann, Gemstones of the world (2001) More from other references |
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Fracture | ConchoidalArthur Thomas, Gemstones (2009) |
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Optical Properties of Turquoise |
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Refractive Index | 1.610 to 1.650Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
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Optical Character | Biaxial/+Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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Birefringence | 0.040Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
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Pleochroism | AbsentWalter Schumann, Gemstones of the world (2001) |
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Dispersion | NoneWalter Schumann, Gemstones of the world (2001) |
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Colour |
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Colour (General) | Light blue, bluish-green, green, greenish-blueUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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Colour (Chelsea Filter) | No reactionHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
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Causes of Colour | Blue, Cu2+ in octahedral coordinationW. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011) |
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Transparency | Translucent,OpaqueHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
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Lustre | Waxy,Dull (Earthy)Arthur Thomas, Gemstones (2009) |
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Fluorescence & other light emissions |
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Fluorescence (General) | Weak; green-yellow, light blueWalter Schumann, Gemstones of the world (2001) More from other references |
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Fluorescence (Long-Wave UV) | Inert to moderate whitish blueHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
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Crystallography of Turquoise |
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Crystal System | TriclinicHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
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Habit | Fine-grained, massive aggregate, partly as nodules or botryoidal groupsUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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Inclusions in Turquoise |
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May contain inclusions of pyrite, calcite, etc - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5 |
Further Information |
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Mineral information: | Turquoise information at mindat.org |
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Significant Gem Localities |
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| China | |
| Liu (1999) | | Kenya | |
| | | Mexico | |
| Sinkankas (1997) | | USA | |
| Sinkankas (1997) |
- Turquoise Mining District (Courtland-Gleeson Mining District)
| Sinkankas (1997) |
- Globe-Miami Mining District
- Miami-Inspiration Mining District
| Sinkankas (1997) |
- Lone Star Mining District (Safford Mining District; Dos Pobres Mining District)
| Sinkankas (1997) |
| Sinkankas (1997) |
| Sinkankas (1997) |
- Silver Lake Mining District
| Sinkankas (1997) |
- Bonanza Mining District (Kerber Creek Mining District; Blake Mining District)
| Sinkankas (1997) |
| Sinkankas (1997) |
| Nevada, Lithographie, 2013, p. 53 |
| Nevada, Lithographie LTD, 2013 |
| Sinkankas (1997) |
| Sinkankas (1997) |
| Sinkankas (1997) |
- Burro Mountains Mining District
| Sinkankas (1997) |
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