Purple "Pimpleback" Shell 8x16mm Faceted Rectangle Bead - 15-16 Inch Shape_Drum An iron oxide-hydroxide mineral

An iron oxide-hydroxide mineral

Discovered in Greenland in the late 1890's

dark specks or veins

though significant deposits have since been found in Brazil and Sri Lanka

2-3 medium ranging 18-25mm

Purple "Pimpleback" Shell 8x16mm Faceted Rectangle Bead - 15-16 Inch Shape_Drum An iron oxide-hydroxide mineralA "pimpleback" is a freshwater mussel (Cyclonaias pustulosa) common in North American rivers, characterized by a thick, yellow brown to brown shell covered in bumps (pustules). While not typically purple, the inner lining (nacre) can be iridescent, and related species in the pimpleback complex are sometimes found in Texas waters.