Epidote

specimen number:
2282035

location:
Thompson Peak, Plumas Co., California, USA

description:
A grouping of fibrous epidote crystals without matrix. In great condition. Collected by Chuck Trantham in 1987.

The Thompson Peak copper mine, situated near Janesville in the Diamond Mountain district of Plumas County, California, is a historic underground operation located near the crest of the Honey Lake fault scarp. Geologically, the deposit consists of hydrothermal copper-bearing vein networks and replacement lenses hosted within Mesozoic granodiorite and associated metamorphic country rocks. The primary mineralization features copper sulfides, chiefly chalcopyrite and bornite, occurring along with pyrite in a quartz and sericite gangue, which underwent localized surface oxidation to produce minor secondary copper carbonates. Discovered around 1905, commercial development and underground tunneling began in earnest under the Thompson Peak Mining Company between 1906 and 1908, with sporadic periods of development, local prospecting, and light ore shipments continuing through the 1910s and 1920s before the mine fell entirely idle.

Charles "Chuck" Trantham was a highly respected geologist and field mineral collector based in California who left a significant mark on the West Coast mineral community. Combining his professional geological expertise with a deep passion for field collecting, Trantham operated CT Minerals for decades, supplying collectors and museums with precisely documented regional specimens. He is particularly remembered for his work in the field during the 1970s and 1980s, which included field-collecting uncommon minerals at various California localities, such as the Junnila benitoite claim in San Benito County and occurrences in Plumas County.

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