Tektite (Indochinite)
Natural Silica Glass var. Tektite · Meteoritic Material / Collector Mineral
Crystal System
Amorphous (Non-crystalline); lacks an internal atomic structure. Habit is typically splash-form (teardrops, spheres, dumbbells) or layered (Muong Nong-type).
Mineral Group
Natural Glass / Tektite
Chemical Formula
SiO2 (70-75%) + Al2O3, K2O, Na2O, CaO, MgO, FeO
Formation Process
Impactite: Formed by the melting of terrestrial crustal rocks during a hypervelocity meteorite impact, ejected into the atmosphere, and rapidly cooled into glass during re-entry.
About This Crystal
The specimen displays a dark, nearly black opaque body with a characteristic pitted or 'pitted-and-grooved' surface texture known as sculpturing. It has a vitreous to sub-vitreous luster on fresh surfaces, appearing waxy or dull when weathered. It is translucent only on very thin edges, showing a brownish-olive tint.
Physical Characteristics
Color: Black to dark olive brown; Streak: White/None (glassy); Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.3–2.5; Tenacity: Brittle; Fluorescence: None.
Optical Properties
Isotropic (Singly refractive); Refractive Index: 1.48–1.51; Birefringence: None; Pleochroism: None; Lacks fire or dispersion due to amorphous nature.
Hardness & Durability
Origin Region
Indochinese strewn field (Thailand, Vietnam, Cambodia, Laos, Southern China). Found in terrestrial sedimentary deposits.
Hardness & Durability
Mohs Hardness: 5.5 to 6.5. Toughness is low (brittle like man-made glass). Sensitive to thermal shock and physical impact.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaning. Store separately from harder gemstones like quartz or topaz to prevent scratching.
Rarity & Value
Relatively common in the Indochinese field, though large or aerodynamically shaped specimens (buttons) are rarer. Value is generally low ($1-$20 for average pieces), primarily determined by weight and surface texture features.
Special Characteristics
Surface features include 'pitted' indentations caused by atmospheric ablation or chemical etching over time. Contains lechatelierite (melted silica) and lacks the water content found in volcanic obsidian.
Lore & History
Historically used as amulets or tools by indigenous cultures. In metaphysical traditions, it is believed to facilitate communication with other worlds and catalyze spiritual growth. It is often associated with the Third Eye and Crown chakras.