An extraordinary example of tyrolite from this long extinct locale. Divergent, lustrous, almost pearly teal blue, foliated blades of tyrolite, accompanied by minor azurite, grace the top edge of this gorgeous and historically significant piece. Tyrolite is a rare and chemically complex calcium copper arsenate-carbonate hydrate with hydroxyl. Small stringers and clusters of blue-green chalcophyllite crystals are also evident. Both species are found as secondary minerals in the oxidized, arsenic-bearing areas copper deposits such as the case at the Centennial Eureka mine. We haven't seen a specimen of this quality in many years. Ex. J. R. Jelks collection with label. I would say that he was one of the most respected collectors of display quality esoterica and rarities in the last half of the 1900s, and many of his pieces remain unique and startling for their rarity.