Kupletskite

This specimen features rich coverage of straw-yellow to bronze-brown acicular crystals of kupletskite, a rare and complex titanium silicate mineral. The kupletskite occurs as fine sprays and isolated needles across a feldspar-rich matrix, often associated with dark green to brown acicular aegirine crystals. Several areas also show cleaved, translucent, dark golden-brown crystals—possibly titanite, though this identification remains unconfirmed.

The specimen originates from the Big Rock Quarry in Pulaski County, Arkansas—an active nepheline syenite quarry owned by 3M Company, located just south of Little Rock near Sweet Home. Mining activity at the site began in the 1870s, and the area also includes an adjacent, now-abandoned sandstone quarry known for quartz veins within the Jackfork Sandstone. Kupletskite specimens from this locality are seldom encountered, and this is a particularly showy and well-formed example. It represents a fine specimen from one of Arkansas’s most significant localities for rare silicate minerals.