2" Siderite Crystals on Chalcopyrite - Peru

This is a cluster of brown rhombohedral siderite crystals that formed over chalcopyrite, collected from the Julcani Mine in Huancavelica, Peru.

Siderite, also known as "chalybite", is an iron carbonate mineral that belongs to the calcite group. It can contain a wide variety of impurities including manganese, magnesium, calcium, zinc and cobalt. Hues of brown are typical for siderite, with the occasional white and gray specimens. It can occur as rhombohedral crystals with rounded faces and in rare cases, it's found as scalenohedral crystals. Botryoidal, concretionary, massive, stalactitic and mammillary are some of the more common formations of siderite.

Being that siderite is such a prevalent mineral, it can be found all around the world in a wide variety of colors and formations. A noteworthy location that produces beautiful gemmy siderite specimens is the Morro Velho Mine in Minas Gerais, Brazil. The crystals collected from here are often translucent, yellow-green in color and form in association with dolomite, cubanite, pyrrhotite and chalcopyrite.

The chemical formula of siderite is FeCO3 with the variable formula including manganese, magnesium, calcite, zinc and cobalt ((Fe,Mg,Ca,Mn,Zn,Co)CO3).

Chalcopyrite is a brass-yellow colored mineral which is one of the most important ores of copper. When weathered chalcopyrite loses it's metallic luster, turning a gray-green color. When acids are present the tarnish can develop a red to blue to purple iridescence.
DETAILS
SPECIES
Siderite & Chalcopyrite
LOCATION
Julcani Mine, Julcani District, Angaraes Province, Huancavelica, Peru
SIZE
2" wide
CATEGORY
ITEM
#173396