Fluorite

specimen number:
9273025

location:
El Filo Mine, Santa Librado, Mapimi, Durango, Mexico

description:
Attractive lustrous and mostly gemmy purple crystals of fluorite to 2.0 cm on edge across the front of matrix. This is in very good condition with just slight cleaving present. All of the prominent crystals are perfect. Very fine for this locality.

The El Filo mine (frequently referred to as the El Filo vein), situated near Santa Librada within the Mapimi Municipality of northern Durango, Mexico, is a localized mining operation famed in the mineral collecting community for producing distinct, sharp cubic fluorite crystals that vary from light lavender to deep violet-purple, often seated on a contrasting white matrix. Geologically, this deposit consists of a series of hydrothermal vein networks cutting through Cretaceous sedimentary limestone units typical of the Sierra Madre Oriental physiographic province. The mineralization process was heavily dominated by late-stage, low-temperature hydrothermal fluids that deposited massive silica and fluorite within fractures, where the veins underwent episodes of structural brecciation and subsequent resilicification, resulting in fluorite cubes that display prominent, well-developed growth spirals on their faces. Historically, small-scale exploratory digging and intermittent extraction occurred during the twentieth century, but targeted mining for commercial collector specimens intensified significantly in the late 1990s and 2000s as mineral diggers recognized the commercial appeal of these unique, highly reactive blue-fluorescing purple cubes. Because of its geographic location within the Mapimi district, production from the El Filo workings has frequently been mislabeled or confused with material from the nearby massive Ojuela mine, yet the characteristic siliceous matrix and complete lack of a petroleum odor remain definitive markers.

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