Moldavite

Moldavite
Moldavite from Dobrkovská Lhotka
General
CategoryGlass
FormulaSiO2(+Al2O3)
Crystal systemAmorphous
Identification
ColorOlive green
Mohs scale hardness5.5 to 7
LusterVitreous
DiaphaneityOpaque, translucent, transparent
Specific gravity2.32 to 2.38
Optical propertiesIsotropic
Refractive index1.48 to 1.54
BirefringenceNone
PleochroismAbsent
DispersionNone
References

Moldavite (Czech: vltavín) is a forest green, olive green or blue greenish vitreous silica projectile glass formed by a meteorite impact in southern Germany (Nördlinger Ries Crater) that occurred about 15 million years ago. It is a type of tektite and a gemstone. Material ejected from the impact crater includes moldavite, which was strewn across parts of Germany, the Czech Republic and Austria.