Tellurium is named from the Latin tellus, earth and was discovered in 1782. Tellurium is occasionally found native, but is more often found as the telluride of gold (calaverite) and combined with other metals. It is recovered commercially from the anode muds produced during the electrolytic refining of blister copper. The U.S., Canada, Japan and Peru are the largest producers of the metal. Crystalline tellurium has a silvery-white appearance, and when pure exhibits a metallic luster. It is brittle and easily pulverized. Tellurium improves the machinability of copper and stainless steel, and its addition to lead decreases the corrosive action of sulfuric acid to lead and improves its strength and hardness. Tellurium is used as a basic ingredient in blasting caps, and is added to iron for chill control. Tellurium is also used in ceramics.