Polybasite with Marcasite

Unknown Owner

A loose cluster of large platy hexagonal polybasite crystals. These are lustrous and metallic, accented with chalcopyrite and marcasite. Slight damage present, this still very nice for this old Mexican classic.The Las Chispas Mine, located in the Arizpe Municipality of Sonora, Mexico, is a historically significant silver and gold deposit. Geologically, it is a low-sulfidation epithermal system consisting of numerous quartz-calcite veins hosted within volcanic rocks, primarily andesitic and rhyolitic tuffs of the Sierra Madre Occidental. The mineralization is noted for its high-grade silver sulfosalt and gold content, often occurring in bonanza-style shoots along structural faults. Historically, the mine was discovered in the late 1800s, with its primary period of production occurring between 1880 and 1930 under the management of various American and Mexican interests. After decades of dormancy and sporadic small-scale activity, modern exploration led by SilverCrest Metals began in 2016, resulting in the construction of a new industrial facility. Commercial production at the modernized site resumed in late 2022, making it one of the highest-grade silver operations currently active in Mexico.