Found this interesting picture crop up on flickr. It’s a reddish mineral named vanadinite (also known as descloizite). The white mineral beneath the vanadinite is barite.
From the Wikipedia entry:
The color is deep cherry-red to brown or black, and the crystals are transparent or translucent with a greasy lustre; the streak is orange-yellow to brown; specific gravity 5.9 to 6.2; hardness 31/2. A variety known as cuprodescloizite is dull green in color; it contains a considerable amount of copper replacing zinc and some arsenic replacing vanadium. Descloizite occurs in veills of lead ores in association with pyromorphite, vanadinite, wulfenite, etc. Localities are the Sierra de Cordoba in Argentina, Lake Valley in Sierra County, New Mexico, Arizona, Phoenixville in Pennsylvania, and Kappel (Eisen-Kappel) near Klagenfurt in Carinthia.
I messaged emeraldcitycreative on flickr about the origins of this specimen. She acquired it from a Spanish miner who originally found it in Morocco.
(Side note: I really need a spell checker with geologic names and terms. All the papers or posts I write are nothing but a sea of red.)
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