Moldavite
Moldavite is named after the the former german name of the river Moldau, Czech Republic, where the material was first found in 1787. Czechs call them "vltavin", after the Czech name for the same river, the Vltava.
Moldavite is a natural glass, a variety of
Tektite. Tektites are formed when terrestrial rock and soil is melted and ejected into space by meteorite impacts, and each impact produces a limited strewn field which is named. Consequently the name "moldavite" can only be used for tektites from one specific impact (in this case the Ries crater in Germany), the strewn field being mainly in the Czech Republic, together with minor neighboring areas of Germany and Austria. It is nonsense for other glasses to be marketed using variations of the name like "African Moldavite" (sic).
Moldavites are the most transparent of all the various types of tektites. They are found in many different color shades between brown and green, but normally only the ones with bottle-green hue are used for faceting. Occasionally faceted green bottle glass gets fraudulently passed off as "moldavite". True moldavite gems can be identified by their vermiform inclusions of lechatelierite (pure silica glass - melted quartz).
General Information |
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A variety or type of: | Tektite |
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Chemical Formula | Walter Schumann, Gemstones of the world (2001) |
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Photos of natural/un-cut material from mindat.org |
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Physical Properties of Moldavite |
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Mohs Hardness | 5.5Walter Schumann, Gemstones of the world (2001) More from other references |
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Specific Gravity | 2.32 to 2.38Walter Schumann, Gemstones of the world (2001) More from other references |
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Cleavage Quality | NoneWalter Schumann, Gemstones of the world (2001) |
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Fracture | ConchoidalWalter Schumann, Gemstones of the world (2001) |
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Optical Properties of Moldavite |
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Refractive Index | 1.48 to 1.54Walter Schumann, Gemstones of the world (2001) More from other references |
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Optical Character | IsotropicUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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Birefringence | NoneWalter Schumann, Gemstones of the world (2001) |
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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) | Bottle-green to brown-greenWalter Schumann, Gemstones of the world (2001) More from other references |
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Causes of Colour | Yellowish green, Fe2+ in octahedral coordination.W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011) |
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Transparency | Transparent,Translucent,OpaqueWalter Schumann, Gemstones of the world (2001) More from other references |
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Lustre | VitreousWalter Schumann, Gemstones of the world (2001) |
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Fluorescence & other light emissions |
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Fluorescence (General) | NoneWalter Schumann, Gemstones of the world (2001) |
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Fluorescence (X-RAY) | A faint yellowish green.Michael O’Donoghue, Gems, Sixth edition (2006) |
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Crystallography of Moldavite |
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Crystal System | AmorphousWalter Schumann, Gemstones of the world (2001) More from other references |
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Geological Environment |
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Where found: | Space or impact (large meteorites)E. Ya. Kievlenko, Geology of gems (2003) |
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Inclusions in Moldavite |
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Gas bubbles, swirl marks - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 2 |
Further Information |
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Mineral information: | Moldavite information at mindat.org |
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Significant Gem Localities |
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