MINERAL OF THE MONTH By Ronald L. Parker, Senior Geologist: Task Fronterra Geoscience, 5650 Greenwood Plaza Boulevard, Suite 105, Greenwood Village, CO 80111 | ron.parker@taskfronterra.com
EPIDOTE The Pistachio Green Mineral
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Euhedral and anhedral epidote crystals surrounded by calcite. This sample is from the Calumet mine NNE of Salida in Chafee County, Colorado. Although the euhedral crystals appear as dark green to greenish black, the granular epidote displays the diagnostic “pistachio green” color. The translucent green crystal in upper right middle is 7 mm tall and displays a hint of vertically oriented striations that are commonly observed on epidote crystal faces. These striations are aligned with the b crystallographic axis, which is almost always the long axis of crystals. Photo by Ronald L Parker.
OUTCROP | May 2016
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Vol. 65, No. 5 | www.rmag.org