Cordierite- Copper Mountain District, Owl Creek Mountains, Fremont, Wyoming, USA For Sale

Dimensions: 3.0 × 3.1 × 2.4 cm
Provenance: Original catalog label No. 202 included; original locality listed as “near Cody, Wyoming.”

A compact Cordierite specimen displaying a muted blue-gray to smoky violet coloration with areas of moderate translucency. Freshly exposed surfaces show a vitreous luster and subtly mottled internal appearance, while numerous intersecting fractures catch the light across the specimen.

Cordierite is a magnesium-aluminum silicate typically associated with metamorphic rocks and is particularly known for its strong pleochroism, which can produce blue, violet, gray, or yellowish tones depending on viewing direction. The geology immediately around Cody is largely sedimentary, with the Absaroka volcanic terrain occurring farther west, while documented Wyoming Cordierite localities occur elsewhere in metamorphic terrains. Cordierite is documented from the Copper Mountain district of Wyoming, where it occurs within the area's ancient metamorphic rocks.