Tektite Value, Price, and Jewelry Information

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TEKTITE: Moldavite, Czechoslovakia (6.4). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Tektites were first discovered in 1787 in Czechoslovakia (then Moravia) near the River Moldau, hence the name moldavite. It has been argued that tektites originated as a result of violent explosive activity on the Moon and were thrown all the way to the Earth’s surface. Other scientists, currently in the majority, argue that tektites are of terrestrial origin. The issue is being debated in a lively way.

Tektite Information

Data	Value
Name	Tektite
Varieties	Australite, Bikolite, Billitonite, Darwin Glass, Moldavite
Stone Sizes	Faceted gems are usually cut from moldavites because the color of these tektites is lighter than most others. The color is a bottle green resembling diopside, and gems up to about 25 carats have been cut, although very large moldavites have been found. Various other tektites from the United States have been cut as curiosities, mostly small. The refractive index of a tektite seems to vary (positively) with iron content.
Formula	Silica (75%) + Al, Fe, Ca, Na, K, Mg, Ti, Mn.
Colors	Black, green, greenish brown, brown in moldavites; other tektites black, colorless to brown.
Fracture	Conchoidal
Hardness	5.5-6.5
Cleavage	None
Crystallography	Amorphous (tektites are natural glasses).
Refractive Index	1.46-1.54
Birefringence	None
Luminescence	None in UV. Yellow-green in X-rays.
Luminescence Present	Yes
Luminescence Type	X-ray Colors
Absorption Spectrum	Not diagnostic. Moldavites may show two vague bands in the blue and orange.
Pleochroism	None.
Optics	Isotropic; N = 1.46-1.54.
Luster	Vitreous.
Specific Gravity	2.21-3.40 (see table).
Transparency	Transparent to opaque.

Optics: Isotropic; N: 1.46-1.54.

Inclusions: Often see numerous rounded or torpedo-shaped bubbles; also swirl striae that are unlike those seen in paste (glass used to imitate gemstones).

Occurrence: Tektites occur worldwide in fields in which the glass bits are literally strewn over the ground, covering a very wide area (see table).

Name	Locality	Maximum Size	Specific Gravity	Refractive Index	Color
Moldavite*	Czechoslovakia	235 grams	2.27-3.40	1.48-1.54	bottle green
Australite*	Australia	218 grams	2.38-2.46	1.50-1.52	black, brown edge
Darwin glass	Tasmania	–	2.75-2.96	1.47-1.48	green, black
Javaite	Java	–	2.43-2.45	1.509	black
Billitonite	Billiton Island (near Borneo)	–	2.46-2.51	1.51-1.53	black
Indochinite*	Indochina	3200 grams	2.40-2.44	1.49-1.51	black
Philippinite (rizalite)	Philippines, especially Luzon	–	2.44-2.45	1.513	black
Ivory Coast tektite	Ivory Coast	–	2.40-2.51	1.50-1.52	black
Libyan Desert Glass*	Libya	4500 grams	2.21	1.462	pale greenish yellow
Bediasite*	Gonzales County, Texas	91.3 grams	2.33-2.43	1.48-1.51	black
Georgia tektite*	Georgia	–	2.33	1.485	light olive-green
Massachusetts tektite*	Martha’s Vineyard, Massachusetts	–	2.33	1.485	light olive-green

Comments: Tektites were first discovered in 1787 in Czechoslovakia (then Moravia) near the River Moldau, hence the name moldavite. It has been argued that tektites originated as a result of violent explosive activity on the Moon and were thrown all the way to the Earth’s surface. Other scientists, currently in the majority, argue that tektites are of terrestrial origin. The issue is being debated in a lively way.

Name: Moldavite is from the River Moldau; other tektite names are from the localities where they occur.