Banded Fluorite and Calcite, Pure Potential Mine, La Paz County, Arizona
Contributed by: Chris Clemens
minID: 51K-WGM
Date: Apr 18th, 2026
Locality: North Geronimo Mine, Silver Mining District, La Paz County, Arizona, USA (See on Mindat)
Size: 7.3 x 5.6 x 8.4 cm
Weight: 292 g
Description:
This banded fluorescent beauty is from the Pure Potential Mine in La Paz County, Arizona, and features alternating bands of red fluorescent calcite and blue fluorite.
The Pure Potential Mine, also known as the North Geronimo Mine, is located north of Yuma, Arizona. No longer active, it is a former underground operation that produced lead, zinc, silver, molybdenum, vanadium and fluorspar. Specimen mining still takes place at the Pure Potential Mine under private claim.
Under longwave UV (365 nm), the fluorite bands show a bright blue response, while the calcite shows only dim red fluorescence. Due to the deep, saturated color of the blue fluorescence of the fluorite, it is not possible to accurately depict the brightness of the response.
Originally posted by Chris Clemens on Nature's Rainbows in 2020.
Summary of luminescence responses:
Calcite (Mindat) (RRUFF)
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Red
- Fluorescence under Longwave (365nm LED) UV light: Blue