Tellurite

This article is about the mineral. For the similarly named Star Trek race, see Tellarite. For the tellurium anion, see tellurite (ion).

Tellurite
240px Tellurite from the Moctezuma Mine, Moctezuma, Sonora, Mexico
General
Category	Oxide minerals
Formula (repeating unit)	TeO2
Strunz classification	04.DE.20
Crystal symmetry	Orthorhombic dipyramidal H-M symbol: (2/m 2/m 2/m) Space group: P bca
Unit cell	a = 5.6 Å, b = 12.03 Å, c = 5.46 Å; Z=8
Identification
Color	Yellow to white
Crystal habit	Flattened prismatic to acicular crystals, radiating groups; powdery, massive
Crystal system	Orthorhombic
Cleavage	Perfect on {010}
Tenacity	Flexible
Mohs scale hardness	2
Luster	Sub-adamantine
Diaphaneity	Transparent to opaque
Specific gravity	5.88 - 5.92
Optical properties	Biaxial (-)
Refractive index	nα = 2.000 nβ = 2.180 nγ = 2.350
Birefringence	δ = 0.350
Solubility	Sleight in water
References

Tellurite is a rare oxide mineral composed of tellurium dioxide (TeO₂).

It occurs as prismatic to acicular transparent yellow to white orthorhombic crystals. It occurs in the oxidation zone of mineral deposits in association with native tellurium, emmonsite and other tellurium minerals. Its name comes from Tellus, which is the Latin name for the planet Earth.

It was first described in 1842 for an occurrence in Faţa Băii, Zlatna, Alba County, Romania.