Tektite | Gemopedia

Tektites are very unique in that they form when a meteorite melts the earth that it comes in contact with. Often, this is in the form of molten rock and sand turned molten from the heat of impact, and may be tossed into the air, raining down as a natural glass. Tektites are named from their locations, i.e. moldavite is from the Moldau river area of the Czech Republic. Common colors of this natural glass are yellow, green, gray to black, and colorless.
Colors
Green, Olive Green, Light Yellow To Yellowish Green, Black, Dark Brown, Colorless

Tektite Classification

Common Name

Tektite

Species

Tektite

Variety

Colors

Green, Olive Green, Light Yellow To Yellowish Green, Black, Dark Brown, Colorless

Alternate Names

Gemstone Groups

Key Separations

refractive index, SR nature, magnification, and specific gravity

Comments

Tektite is a general term used for natural glasses formed by meteoric impacts. Australite: dark or black disc, bowl or button-shaped Tektites from Southern Australia and Tasmania. Bikolite: Tektites from the Bikol area of the Philippines. They occur as spheres with a breadcrust crack appearance and grooved curved polygonal flakes. Billitonite are from the Billiton Island between Sumatra and Borneo. The acidic waters of the area make Billitonite more etched than other varieties of tektites. Darwin glass: natural glass from just south of Queenstown, Tasmania it is thought it comes from the Darwin crater impact site. Moldavite green variety of tektites from the Czech Republic. Libyan desert glass: light yellow to greenish yellow from the White Desert in Egypt. Indochinite: dark mostly black and found in Vietnam, Laos, Cambodia, Thailand and southern China

Tektite Optical Properties

Transparency

Translucent - Opaque

Refractive Index

1.49-1.52

Birefringence

Optic Character

NA

Optic Sign

NA

Polariscope Reaction

Singly Refractive (SR) With ADR

Fluorescence

SWUV: Inert
LWUV: Inert

CCF Reaction

Pleochroism

None

Dispersion

Comments

Tektite Chemistry & Crystallography

Chemical Name

silica

Chemical Formula

SiO2 (75% silica+Al, Ca, Fe, K, Mg, Mn, Na, Ti)

Synthesis

Crystal System

NA

Classification

Mineraloid

Nature

Natural

Crystallinity

Amorphous

Comments

Tektite Characteristic Physical Properties

Hardness

5.5-6.5

Streak

Specific Gravity

2.34-2.51

Toughness

Poor

Inclusions

Tektites often have round and elongated gas bubbles, flow lines and a roiled, cloudy or turbid appearance.

Luster

Vitreous

Stability

Fracture

Conchoidal

Cleavage

None

Comments

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