Chemical composition -- Primarily amorphous silica (glass).
Color -- Black, green, brown.
Optics -- R.I. 1.46-1.54,
Durability -- Hardness 5.5-6.5. Brittle.
Crystal structure -- Amorphous.
Specific Gravity-- 2.2-2.9.
Sources -- Tektites are found scattered around the globe and are widely believed to be meteoritic debris (or, alternatively, volcanic debris). Moldaviteis tektite from Moravia (Czechoslovakia) near the River Moldau, where it was first discovered in 1787.