I am told that these were mined prior to 1850, and I can say that I have only seen a handful of specimens in 20 years of dealing. Perhaps 5 pieces in all, several of them frankly just reference material. This is probably the most aesthetic of those few, that I cna recall. This beautiful and historic specimen is composed of roseate crystals of radiating covellite that are partially coated by a druse of secondary pyrite. The iridescent, neon blue, color along with the lustrous pyrite and rosette form, make this specimen both historic AND fine...that great merger I love to get. This specimen compares, surprisingly, quite favorably with the best covellites from Butte, Montana. And I have to say that a Butte piece of this caliber, would sell for even more money though it is more common material (wiht more people systematically looking for one). This specimen is GORGEOUS, BETTER In PERSON!