Schorl (SIL-0004)

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Classic Mexican specimen, this one a fine grouping of stalactitic velvety black crystallized schorl. In excellent condition all around. The Santa Cruz mining area, located within the Santa Cruz Municipality in the northern portion of the Sonora state, Mexico, represents a historic mineral district mined primarily via underground tunnels and shafts for base metal and silver ores, while noted among mineralogists for producing sharp crystals of the iron-rich tourmaline group mineral known as schorl. Geologically, the district is situated within the prolific copper-bearing porphyry and skarn belts of northwestern Mexico, where mid-Tertiary to Cretaceous-age granitic and granodioritic plutons intruded through older sedimentary sequences and Precambrian basement complex rocks. This intense magmatic activity generated widespread hydrothermal fracturing and contact metamorphism, creating rich quartz veins, pegmatitic lenses, and alteration zones where robust, jet-black prismatic crystals of schorl tourmaline precipitated alongside quartz, feldspar, and associated sulfide mineralization. Historically, silver and copper extractions in the broader Santa Cruz vicinity dates back to localized Spanish colonial prospecting in the late eighteenth and nineteenth centuries, followed by modern mechanized underground development by American and Mexican mining concerns during the early to mid-twentieth century. While large-scale commercial milling of primary industrial base metals peaked and subsequently declined toward the late twentieth century due to fluctuating global commodity markets, the district continues to experience intermittent, small-scale artisanal mining, exploratory core drilling by corporate syndicates, and targeted mineral specimen recovery from local outcroppings and old mine dumps through 2026.