Sphalerite with Quartz

specimen number:
2063617

location:
Sheffler Mine, Alexandria, Clark Co., Missouri, USA

description:
An open pocket or geode half, this lined with colorless crystallized quartz. A grouping of lustrous black sphalerite crystals measuring to 1.5 cm in size are present along half of this pocket. One of the sphalerite crystals has a cleaved face where the geode was broken in half. All of the other sphalerite crystals are in perfect condition. The specimen comes with a previous label from the collection of Ray DeMark. This was collected by Rex Nelson in June, 2004.

The Sheffler Mine (also known as Sheffler Rock Shop and Geode Mine) near Alexandria in Clark County, Missouri, is situated within the famous Keokuk geode region, where geodes occur abundantly in the Mississippian-age Warsaw Formation. Geologically, these spherical rock structures formed through secondary mineralization in cavities within argillaceous limestone and shale matrix, producing hollow nodes lined with quartz crystals, chalcedony, pink scalenohedral calcite, pyrite, kaolinite, and occasional sphalerite. Beginning in the mid to late 20th century as a private surface mining operation, the site transitioned into a famous fee-mining destination and commercial rock shop. Today, mineral collectors from around the world visit the location to excavate these classic Mississippian geodes directly from the shale and limestone layers.

Questions about this specimen?
Send an email or call us: 314-341-1811.