Tektite

Hardness: 5.5-6.5 (Mohs scale); Color: Black or dark brown; Luster: Vitreous (glassy); Crystal structure: Amorphous (non-crystalline); Cleavage: None; Specific Gravity: 2.3-2.5

Tektites are formed during hypervelocity meteorite impacts on Earth. The intense heat and pressure melt terrestrial rocks, ejecting them into the atmosphere where they cool rapidly into glass before landing back on Earth. Most Indochinites are approximately 700,000 to 800,000 years old.

Primarily used for ornamental jewelry, metaphysical collecting, and scientific study of meteorite impact events.

Tektites contain almost no water content (about 0.005%), which is much lower than terrestrial volcanic glass like obsidian. The teardrop or button shapes are a result of aerodynamic ablation during re-entry into the atmosphere.

Identify in the field by searching for pitted, aerodynamically shaped black glass in known strewn fields (like Southeast Asia or Australia). They lack the gas bubbles and flow lines usually seen in slag.