Siderite on Sphalerite (ex Brian Kosnar Collection)

Item Description

These classic Siderite specimens from the Eagle Mine are some of the most recognizable and attractive examples of the species from any mine in Colorado. This mine is long defunct and will never produce these specimens again. They are highly prized among Colorado collectors for their unique form and obvious beauty. They are not the typical blocky rhombic habit like those seen from a lot of other ore bodies in Colorado, but rather highly compressed rhombs that can often form beautiful "rosettes". This piece hosts many sharp, semi lustrous, pinkish-brown color flattened rhombohedra of Siderite on black Sphalerite matrix. The largest rhomb measures 6 mm across. It should be noted that there is likely a bit of manganese in these crystals, which means they are trending towards Rhodochrosite, but without analysis, it would be hard to say whether they are manganese-bearing Siderite or iron-bearing Rhodochrosite. The piece is from the collection of Brian Kosnar with a label from Silver Capital Arts in Wallace, Idaho.