Calcite, Willemite and Fluorite - Hull Mine, Arizona

Contributed by: FMS Admin
minID: RFE-H83
Date: May 12th, 2026
Locality: Hull Mine, Hull Mine group (Rialto Mine group; Hull group of claims; Rialto claims), Buckeye vein group, Castle Dome Mine group, Castle Dome Mining District, Castle Dome Mountains, Yuma County, Arizona, USA (See on Mindat)
Size: 7 x 4.7 x 10.8 cm

Description:
Nice cabinet-sized specimen of calcite (red fluorescence), willemite (green fluorescence) and fluorite (blue fluorescence), from the Hull Mine, Castle Dome Mining District, Yuma County, Arizona. In the first image below, the specimen is shown fluorescing under shortwave UV + midwave UV combined (the calcite fluoresces brighter with midwave UV); in the next images, the specimen is shown, respectively, under shortwave UV, longwave UV and in visible light, then the back side is shown in the same order.

Originally posted by Frédéric Messier Leroux on Nature's Rainbows in 2022.

Fluorescence under midwave and shortwave UV light.

Fluorescence under shortwave UV light.

Fluorescence under longwave UV light.

Normal light.

Fluorescence under midwave and shortwave UV light. Side 2.

Fluorescence under shortwave UV light. Side 2

Fluorescence under longwave UV light. Side 2.

Normal light. Side 2.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

• Fluorescence under Midwave (305nm LED) UV light: Red
• Fluorescence under Shortwave (255nm LED) UV light: Red

• Fluorescence under Longwave (365nm LED) UV light: Blue
• Fluorescence under Shortwave (255nm LED) UV light: Blue

• Fluorescence under Shortwave (255nm LED) UV light: Green