Uranopilite - Barbosa Shaft, Karlovy Vary District, Karlovy Vary Region, Czech Republic

(UO₂)₆(SO₄)O₂(OH)₆ · 14H₂O

Uranopilite from the Barbosa Shaft in Jáchymov, Czech Republic, is a striking secondary uranium mineral known for its bright yellow, fibrous to powdery crystalline habit. This hydrated uranium sulfate forms as a post-mining alteration product in uranium-rich environments, often appearing in delicate, radiating aggregates or crusts on host rock surfaces. The Barbosa Shaft, part of the historic Jáchymov mining district, is renowned for producing exceptional uranium minerals, and Uranopilite from this locality is no exception. Its vibrant coloration and silky texture make it a standout specimen, highly valued by collectors of rare uranium minerals.

Jáchymov has a long and storied history as one of the world’s most famous uranium mining regions, contributing significantly to early nuclear research. Uranopilite specimens from the Barbosa Shaft not only serve as fascinating mineralogical curiosities but also highlight the chemical weathering processes that affect uranium ores over time. Due to its water-soluble nature and delicate crystal structure, this mineral requires careful handling and proper storage to preserve its integrity. For those interested in the unique secondary uranium minerals of historic mining sites, Uranopilite from Jáchymov represents an outstanding and scientifically significant addition to any collection.

Approx. specimen size: 13mm x 12mm x 10mm

Approx. specimen activity on an SE International Ranger EXP: 40 000 cpm