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. Color is tin white often with a muted multi-colored iridescent tarnish. Luster is metallic.
Crystals are opaque.
Fracture is uneven. Streak is tin white. Associated Minerals include poughite , gold , sylvanite and calaverite . Best Field Indicators are tarnish, density, color and cleavage.