Cassiterite

specimen number:
2354179

location:
Hill City, Pennington Co., South Dakota, USA

description:
Sparse crystalline and massive cassiterite throughout this muscovite and quartz matrix. Interesting old time specimen, this comes with an antique label from the collection of Ernest Chapman.

Located in the Black Hills of Pennington County, South Dakota, the geology surrounding Hill City is defined by Proterozoic crystalline schists heavily intruded by granitic pegmatites. Prospectors first discovered cassiterite, the primary tin oxide mineral, in the region during the tin boom of the late nineteenth century, leading to the formation of early operations such as the Etta Mine and the Harney Peak Tin Mining Company. Hydrothermal activity within these pegmatites led to the concentration of cassiterite, which occurs as dark brown to black subhedral crystals and metallic granular masses within quartz and feldspar matrix. Although early commercial tin mining ultimately failed to deliver sustained economic success due to low ore grades, Hill City became historically significant as one of the few major tin-producing districts in North America, and old mine dumps continue to be known among mineral collectors for producing notable tin ore specimens.

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