THE MINERAL TELLURIUM

Chemistry: Te, Elemental Tellurium
Class: Elements
Uses: A minor ore of tellurium and as mineral specimens.
Specimens

Native tellurium is a rare mineral. When it does occur it is often found with gold and gold tellurides such as sylvanite and calaverite.

The metal tellurium is mostly used in alloys with other metals. It is added to lead to improve its strength and durability. In steel and copper it makes the metals more workable. Tellurium is also used in blasting caps.

PHYSICAL CHARACTERISTICS:

Color is tin white often with a muted multi-colored iridescent tarnish.
Luster is metallic.
Transparency: Crystals are opaque.
Crystal System is trigonal; 3 2
Crystal Habits include prismatic crystals but more commonly massive as vein fillings.
Cleavage is good in three directions (prismatically) and poor in a fourth (basal).
Fracture is uneven.
Hardness is 2 - 2.5
Specific Gravity is 6.1 - 6.3 (unusually heavy even for metallic minerals)
Streak is tin white.
Associated Minerals include poughite, gold, sylvanite and calaverite.
Notable Occurrences include Lincoln County, Nevada, New Mexico and at Cripple Creek, Colorado, USA; Romania and Australia.
Best Field Indicators are tarnish, density, color and cleavage.