2" Rosasite and Selenite Crystal Association - Utah

This colorful specimen contains deep blue-green colored, botryoidal rosasite formations, some of which are enshrouded in a thin layer of beautifully transparent selenite crystals. It was collected from the Hidden Treasure Mine in the Ophir District of Utah, a location that's well known for its zinc and copper mineral deposits. Small amounts of blue azurite and green malachite can be found peppered throughout the rock matrix.

Rosasite is a secondary mineral that forms in oxidation zones of copper-zinc deposits, generally forming a fibrous botryoidal sphere that can appear vitreous and silky. While typically featuring a blue-green color, colorless specimens are not unheard of. The chemical formula of rosasite is CuZnCO3(OH)2.

Selenite is a variety of gypsum, a soft sulfate mineral composed of calcium sulfate dihydrate (CaSO4 · H2O). When chemically pure, gypsum is transparent and colorless, but impurities give the gypsum a diverse range of colors and formations. Desert rose selenite and satin spar are just a few of the varieties of gypsum known to have formed though hydrothermal processes.

Malachite is an intense green copper-based mineral that can be found in a wide variety of forms. Malachite can grow in botryoidal masses, stalactitic formations, and reniform formations, typically as a tight cluster of fanning fibrous needles that make up a seemingly solid mass. As layers continue to stack during formation, banded patterns can sometimes begin to take shape, explaining the rings in all shades of green seen on most polished malachite specimens.

Malachite results from the weathering of other copper ores, and is very often found associated with other copper-based minerals such as azurite and chrysocolla. It can be found in copper deposits around the world, but the Democratic Republic of the Congo is the primary source for polished malachite and mineral specimens.

Malachite has been prized since ancient times, first as a utilitarian copper ore, then as an ornamental stone. Due to its value as a decorative stone, it is rarely mined as a copper ore anymore.

Azurite is a copper carbonate hydroxide mineral best known for its beautiful and vibrant blue appearance. Azurite typically forms in nodular formations with other colorful, copper-rich minerals. It is a secondary mineral that precipitated in pores, crevices, and caverns from water with high concentrations of carbon dioxide.

Azurite and malachite are known to form in union with each other since their chemical makeup is very similar. In fact, the presence of more or less water in the location of formation is enough to determine whether an abundance of malachite over azurite, or vise-versa, will accumulate.
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DETAILS
SPECIES
Rosasite & Selenite
LOCATION
Hidden Treasure Mine, Ophir District, Utah
SIZE
2 x 1.3"
CATEGORY
ITEM
#109790