Metallic masses and crystalline glaucodot on matrix with safflorite. The specimen comes with a previous label from the collection of Jack Nieburger.Located in the Quartzburg district of Grant County, Oregon, the Standard Mine sits within a geologically complex zone featuring hydrothermally altered igneous host rocks where cobalt, copper, and gold mineralization occurs along fracture-filled veins. Mining operations began in the late nineteenth century and continued periodically through the mid-twentieth century, with miners working underground shafts primarily for copper and cobalt ores. Among mineral collectors, the locality is notable as one of the few recognized American sites for glaucodot, an iron cobalt arsenic sulfide mineral. Glaucodot from the Standard Mine typically occurs as small, metallic, silver-white to steel-gray crystalline aggregates embedded in quartz and associated sulfide matrix, making specimens from this historic Western locality highly valued in mineral collections.
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