Physical Properties of Moldavite
Composition: Varies but is mostly silica glass with impurities of magnesium, iron and other elements.
Specific Gravity: Approximately 2.5
Luster: Vitreous to dull
Refractive Index Single refraction from 1.48-1.5
Birefringence: None
Hardness: ( Mohs' scale ): 5~6
Cleavage:  None
Fracture:  Conchoidal
Streak: White
Crystal structure: Amorphous ( not crystallized )

Table information taken from http://www.taiwanfm.com.tw/mineral/moldainfor.htm and
Background image taken from www.dragon-vds.com/2d_meteorites.php