Purple "Pimpleback" Shell 8mm Faceted Coin Bead - 15-16 Inch Shape_Coin Lepidocrocite forms when iron-containing substances

Lepidocrocite forms when iron-containing substances rust underwater

These mixed stone strands have a great pop of color making them perfect for when you're making that unique and colorful piece of jewelry

Andalusite is a fascinating aluminum silicate mineral known for its strong pleochroism—the ability to display multiple colors from different angles

Gem Silica is the rarest and highest form of Chrysocolla

but its identity is complicated

Purple "Pimpleback" Shell 8mm Faceted Coin Bead - 15-16 Inch Shape_Coin Lepidocrocite forms when iron-containing substancesA "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.