igneous
Tektite (Indochinite)
Tektite (Amorphous Silica Glass), SiO2(Al2O3)
Hardness: 5.5–6.5 (Mohs scale); Color: Black to dark brown (translucent on thin edges); Luster: Vitreous to dull; Structure: Amorphous (non-crystalline glass); Cleavage: None (conchoidal fracture); Specific Gravity: 2.3–2.5
- Hardness
- 5
- Color
- Black to dark brown (translucent on thin edges)
- Luster
- Vitreous to dull
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Physical properties
Hardness: 5.5–6.5 (Mohs scale); Color: Black to dark brown (translucent on thin edges); Luster: Vitreous to dull; Structure: Amorphous (non-crystalline glass); Cleavage: None (conchoidal fracture); Specific Gravity: 2.3–2.5
Formation & geological history
Formed from terrestrial debris ejected during meteorite impacts. The extreme heat and pressure melt local rocks into glass, which cools while falling back through the atmosphere. This specimen is part of the Australasian strewnfield, formed approximately 790,000 years ago.
Uses & applications
Primarily used by collectors and in metaphysical jewelry. Historically used by ancient cultures for tools and talismans. Because of its unique origin, it is highly valued in scientific research regarding impact events.
Geological facts
Indochinites are the most common type of tektite. Unlike moon rocks or meteorites, tektites are actually terrestrial rocks that 'took a trip' to the edge of space and back. Some reach such high velocities that they melt into 'flanged buttons' due to atmospheric ablation.
Field identification & locations
Identify in the field by looking for a pitted, 'dimpled' surface (lechatelierite bubbles) and conchoidal (shell-like) fractures. Heavily concentrated in Southeast Asia (Vietnam, Thailand, Cambodia). Can be distinguished from obsidian by its lack of water content and its pitted skin.
