Tektite
Indochinite Tektite (Impact Glass) · Meteoritic Material / Collector Mineral
Crystal System
Amorphous (Non-crystalline glass); habit is splash-form, aerodynamically shaped
Mineral Group
Natural Glass (Tektites)
Chemical Formula
SiO2 (~75%) + Al2O3 (~12%) + FeO, MgO, K2O (variable traces)
Formation Process
Terrestrial impact: formed from terrestrial rock that was melted and ejected into the atmosphere by a meteorite impact, then cooled during re-entry
About This Crystal
Deep black to dark brownish-green when held to light; opaque to translucent on thin edges. The surface is distinctly pitted and etched with 'cupules' or 'regmaglypts' formed by atmospheric ablation. Luster is vitreous (glassy) to sub-metallic on fresh surfaces.
Physical Characteristics
Black color; white streak; no cleavage; conchoidal fracture; specific gravity 2.3–2.5; generally non-fluorescent under UV light; non-magnetic.
Optical Properties
Isotropic (singly refractive); refractive index 1.48–1.51; no pleochroism or birefringence as it is a glass.
Hardness & Durability
Origin Region
Indochinese strewn field (Thailand, Vietnam, Cambodia, Laos, Southern China)
Hardness & Durability
Mohs hardness 5.5 to 6.5; brittle; fair toughness but prone to chipping; similar durability to obsidian.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic cleaners which may aggravate internal stress fractures; store separately from harder gems like quartz or sapphire.
Rarity & Value
Relatively common in the Indochinite strewn field; value is primarily determined by size, aerodynamic shape (buttons, teardrops), and surface texture. Generally affordable.
Special Characteristics
Pitted 'sculpted' surface caused by high-velocity flight through the atmosphere; internal bubbles/lechatelierite (high-temperate silica glass) inclusions.
Lore & History
Historically used as talismans in Southeast Asia; traditionally believed to be 'stones of the sky.' In metaphysical practices, it is associated with the Third Eye chakra and believed to assist in communication with other worlds or astral travel.