6.3" Polished Wild Horse Magnesite Section - Arizona

About Wild Horse Magnesite

Wild Horse Magnesite—often marketed as “Crazy Horse Stone”—is a striking semi-precious gemstone prized for its bold contrast of creamy white magnesite veining against a deep red-brown, hematite-rich matrix. It is found exclusively near the Globe Copper Mine in southeastern Arizona, making it a distinctly American lapidary material with a limited and highly localized source.

Geologically, this stone forms through low-grade metamorphism, typically between 200–320°C under relatively low pressure. During this process, magnesium-rich host rock interacts with carbonate-bearing fluids, precipitating networks of white magnesite that branch, swirl, and plume through the surrounding iron-stained rock. The result is the stone’s signature patterning: patches and plumes of snow-white magnesite interwoven with mottled grey, chocolate, and russet hues created by hematite and other iron oxides.