Tourmaline on Feldspar

This tourmaline formed within granitic pegmatites, where boron-rich fluids crystallized alongside feldspar during the final stages of magma cooling. The Mesa Grande district is a classic Southern California locality, known for producing fine tourmaline associated with feldspar and other pegmatite minerals.

Contrasting dark, prismatic tourmaline against light feldspar, this specimen reflects the slow, late-stage processes of pegmatite formation and the rich gem-bearing history of the region.