History · Geology
About Shimen Realgar-Orpiment Mine
The Shimen (石门) realgar-orpiment mine in northwestern Hunan is the global type-quality producer of crystallized realgar and orpiment specimens. For collectors of As-S minerals, Shimen is the unrivaled benchmark.
Geology
The deposit is a low-temperature epithermal As-Sb system hosted in Cambrian carbonates. Realgar-orpiment-stibnite veins fill faults and breccias, with calcite and barite as gangue. Mining has been active since the 14th century but high-quality crystals emerged commercially only in the 20th century.
Notable Minerals
Realgar (cherry-red prismatic crystals to 10+ cm — best in the world), orpiment (golden-yellow cleavable masses and prismatic crystals), stibnite, calcite, barite, and rare getchellite. The realgar-orpiment association on white calcite is the iconic image.
Collector Notes
Shimen realgar is light-sensitive and degrades to pararealgar over years — best stored in darkness. Top-grade specimens command four-to-five-figure prices internationally.
