Silver

Silver is a native element, a metal (Ag) that occasionally occurs uncombined in nature, though most silver is locked up in sulfide ores rather than the native metal. Native silver forms in the oxidation and enrichment zones of silver ore deposits, where silver-bearing solutions deposit metallic silver in cavities and fractures. Unlike gold, native silver is relatively uncommon - most of the world's silver is extracted from sulfide minerals like argentite (silver sulfide) and as a byproduct of lead and copper mining.

When native silver does occur, it can take spectacular forms: wire silver (twisted, hair-like wires), dendritic silver (branching tree-like growths), and crystalline silver (cubic crystals, rare and highly valued). The finest wire silver specimens from Kongsberg, Norway, and various Mexican mines are among the most striking mineral specimens in any category.

Silver tarnishes readily in air, forming a black coating of silver sulfide (acanthite) when exposed to sulfur compounds. This tarnishing tendency means native silver specimens require careful storage and occasional cleaning. Fresh native silver has a brilliant mirror-like luster unmatched by any other naturally occurring metal.

Native silver is identified by its bright white metallic luster (when untarnished), high density (10.5), malleability, and tendency to tarnish black. The silver-white streak on a streak plate is diagnostic.

Distinguish from galena (lead sulfide - cubic crystals, perfect cleavage, not malleable), platinum (much denser at 21.5, doesn't tarnish), and nickel (harder, magnetic). Silver's combination of white metallic luster, malleability, and tarnishing behavior is unique.