Linarite

Linarite is a hydrous sulfate that generally forms in oxidized zones around Pb-Cu ore deposits. Traditionally classed as secondary weath-ering-induced minerals, it has become clear that the low-temperature processes involved in the formation of such minerals involve the cycling of toxic metals from the meteoric system.

The Grand Reef Mine, a probably small and less known locality in industry, however, produces the best linarite in the world. The mine exploits a small epithermal lead-copper-silver deposit, which is hosted by a silicified breccia. The breccia is highly resistant, forming a precipitous cliff, locally known as the ”reef,“ from which the name of the mine is derived. Veins of galena follow irregular fractures in the breccia, and minor amounts of copper sulfides associated with the galena are altered principally to linarite and caledonite.

Most of linarites In worldwide are micromount, typically few mm scale elongated crystal with 1~2mm width. Linarite from Grand Reef Mine can be cm scale and gemmy quality, although clusters, coating or overgrowth are way more common, single gemmy crystals over 1cm have documented, however, extremely rare.

This doubly- terminated toenail specimen was trimmed from a miniature. Resulted two specimen, this is one of them, the best one I ever seen, and I am pleased for having it as one of my core thumbnail/toenail collections.

3.4cm, xl 1.8cm, Grand Reef Mine, Laurel Canyon, Grand Reef Mountain, Klondyke, Aravaipa Mining District, Graham County, Arizona, USA

Jingnan (Tom) Zhang Coll & Photo