Crystallized, dendritic Silver specimen from the historic, Cobalt, Ontario, Canadian mines.  This .5 cm. thick slab has been cut with a diamond saw, with both sides polished. Native Silver is hosted in a Dolomite matrix.  Unique, veinlets and dendritic Silver exhibits brilliant silver metallic luster.  This specimen comes from the old, 1900s historic Castle Mine.   Massive Native Silver was discovered in veins in Pre-Cambrian Greenstones in Cobalt, Ontario in 1903 and hundreds of mines were eventually exploiting the metal. By 1915 the mines were essentially exhausted. Some minor mining occurred later.  Native Silver was found in several important American mining districts historically. Virginia City, Tonopah, Austin, and Rochester were the most productive Nevada mines. Mexico produced huge amounts as did several South American countries. Today a few of these American mines are still producing Silver...but not Native Silver. Weighs  2.8 Oz.