Calcite, Fluorite, Willemite - Black Rock Mine, Arizona

Contributed by: FMS Admin
Date: May 25th, 2026
Locality: Black Rock Mine, Black Rock Wash, Silver Mining District, La Paz County, Arizona, USA (See on Mindat)
Size: 3 x 4 inches

Description:
Arizona has a lot of great mines and stunning material. Here's a nice one from the Black Rock Mine in Yuma County, Arizona. Great patterns of calcite and willemite, with fluorite mixed in.

Originally posted by Fire Viper on Nature's Rainbows in 2016.

Fluorescence under longwave and shortwave UV light.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Red

• Fluorescence under Longwave (365nm LED) UV light: Blue

• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green