Andradite (SIL-0003)

specimen number:
9273074

location:
Prieta Linda Mine, Chihuahua, Mexico

description:
Lustrous black crystals of andradite measuring to 2.5 cm in size across the front of matrix. In excellent condition.

The La Prieta Linda mine, also historically documented as the Ojos Espanoles mine and located near Ciudad Lazaro Cardenas within the Julimes Municipality of Chihuahua, Mexico, is a classic localized mining excavation celebrated among mineralogists for producing magnificent, highly lustrous crystal specimens of sharp dodecahedral andradite garnet, particularly the jet-black, yttrium-bearing variety known as melanite. Geologically, the deposit is a characteristic contact-metamorphic skarn system developed along the eastern flank of the regional carbonate sequences, where intrusive Tertiary-age igneous magmas forced their way through thick Cretaceous-age sedimentary limestones. This intense thermal and chemical reaction recrystallized the surrounding host rock into a dense silicate skarn assemblage, generating open solution vugs and crystalline pockets where rich calcium-iron hydrothermal fluids could freely precipitate large, glassy, and visually striking formations of black andradite garnets resting on a massive garnet and calcite matrix. Historically, organized surface exploration and localized open-cut quarrying at the skarn outcroppings began in earnest during the late twentieth century, with targeted specimen extraction peaking intermittently throughout the 1980s and 1990s as small private syndicates recognized the unique aesthetic value of the localized pockets. Because the underground workings and open cuts were operated primarily by selective manual methods aimed at preserving delicate crystal clusters rather than bulk automated ore milling for industrial iron smelting, the mine avoided massive mechanical obliteration, remaining a specialized reference locality for collector-grade Mexican garnets intermittently active through 2026.

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