Rock Identifier
Native silver specimen (Silver (Ag), probably crystallized native silver with associated gangue) — mineral
mineral

Native silver specimen

Silver (Ag), probably crystallized native silver with associated gangue

AI-generated identification · may be incorrect

Metallic gray to black color and luster; likely Mohs hardness 2.5–3, cubic crystal system, with excellent malleability and high specific gravity (~10.5). The branching, wire-like masses are characteristic of native silver, though the dark surface may reflect tarnish or oxidation.

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Physical properties

Metallic gray to black color and luster; likely Mohs hardness 2.5–3, cubic crystal system, with excellent malleability and high specific gravity (~10.5). The branching, wire-like masses are characteristic of native silver, though the dark surface may reflect tarnish or oxidation.

Formation & geological history

Formed by hydrothermal mineralization in fractures and veins, commonly with quartz, calcite, and sulfide minerals; the display label appears to reference the Cobalt mining district in Ontario, Canada, where exceptionally rich native-silver specimens formed during the Precambrian (~1.8 billion years ago).

Uses & applications

Primarily a collector and museum specimen; silver is widely used in electrical contacts, electronics, solar technology, photography, utensils, and jewelry.

Geological facts

Cobalt is famous for spectacular native-silver “wire silver” and dendritic specimens. Silver tarnishes readily through reaction with sulfur-bearing compounds, producing a dark surface coating.

Field identification & locations

Identify by its heavy metallic appearance, gray-black tarnish, softness, and distinctive wires or branching masses; distinguish it from galena by silver’s malleability and lack of cubic cleavage. Common localities include Cobalt and Silver Islet, Ontario; Batopilas, Mexico; and Freiberg, Germany.