Tektite
Tektite (Natural silica-rich glass) · Meteoritic Material / Collector Mineral
Crystal System
Amorphous (Non-crystalline material with no internal structure); Habit: Irregular, pitted, or splash-form (teardrops, spheres, dumbbells)
Mineral Group
Natural Glass (Non-mineraloid material resulting from terrestrial impact)
Chemical Formula
SiO2 (approx. 75%) + Al2O3, FeO, MgO, CaO, Na2O, K2O
Formation Process
Terrestrial impact: Formed when a large meteorite strikes Earth, melting local terrestrial rock and ejecting it into the atmosphere where it cools rapidly into glass.
About This Crystal
A dark, typically black or deep brownish-green glass specimen. It features a characteristic pitted or 'sculpted' surface (regmaglypts) caused by atmospheric ablation. It is generally opaque to translucent on thin edges with a vitreous to dull luster.
Physical Characteristics
Color: Black to brownish-black; Streak: White/None; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.2–2.5; Fluorescence: Usually inert; Tenacity: Brittle.
Optical Properties
Refractive Index: 1.48–1.51 (Isotropic); Birefringence: None; Pleochroism: None; Optical phenomena: Can contain unique microscopic flow lines and 'Lechatelierite' (pure silica glass) inclusions.
Hardness & Durability
Origin Region
Notable strewn fields include the Indochinite field (Southeast Asia), Australite field (Australia), Moldavite field (Czech Republic), and Bediasite field (Texas, USA).
Hardness & Durability
Mohs hardness: 5.5 to 6.5; Toughness: Poor (brittle like man-made glass); Stability: Stable but sensitive to sudden thermal shock and physical impact.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic cleaners or steam cleaners which may cause the glass to crack. Store separately from harder gemstones like quartz or topaz.
Rarity & Value
Common (for Indochinites) to Rare (for Moldavites or specific splash forms). Value is determined by weight (grams), shape symmetry, and locality. Most black tektites are affordable collector items.
Special Characteristics
Pitted 'aerodynamic' surface textures; flow structures; extremely low water content compared to volcanic obsidian; potential presence of microscopic bubbles of vacuum-like gas.
Lore & History
Historically used as talismans and tools by ancient cultures in Southeast Asia and Australia. In metaphysical traditions, it is often associated with the Third Eye chakra, believed to assist in extraterrestrial communication and rapid spiritual growth.