Metahewettite (w/ Carnotite & Tyuyamunite) - Uravan Mining District, Montrose County, Colorado, USA

CaV₆O₁₆ · 3H₂O

Metahewettite, often found alongside carnotite and tyuyamunite, is a rare secondary uranium-vanadium mineral that adds unique character to specimens from the Uravan Mining District in Montrose County, Colorado. This mineral forms as fine, dark reddish-brown to black crusts or thin coatings on sandstone and other oxidized host rocks. Metahewettite is a hydrous calcium uranium vanadate and typically develops in arid, oxidizing conditions where uranium-vanadium minerals are concentrated through weathering and groundwater processes. In the Uravan District, it is commonly associated with bright yellow carnotite and greenish-yellow tyuyamunite, creating striking visual contrasts that make specimens highly collectible and geologically fascinating.

The presence of carnotite and tyuyamunite with metahewettite underscores the district's role as a classic locality for uranium-vanadium deposits, which were heavily mined during the mid-20th century. These minerals reflect the complex interplay of oxidation-reduction processes that enriched the sandstone formations in uranium and vanadium. Metahewettite, being less common, offers a glimpse into the diversity of secondary uranium mineralization in the region and serves as a key indicator of post-depositional alteration in the ore zones. Collectors and geologists alike value specimens from the Uravan Mining District for their vivid coloration, mineralogical associations, and historical significance in the uranium mining era of the Colorado Plateau.

Approx. specimen size: 78mm x 45mm x 35mm

Approx. specimen activity with SE International Ranger EXP: 20 000 cpm