Fluorescent Mineral Database

A new secret project! Trying to create a nice Fluorescent Mineral Database (FMDB), which would be searchable by mineral, locality, and luminescence properties. Also making it easy for people to contribute with their own specimens!

Chalcedony & Calcite from Nebraska, USA

Contributed by: Simone Conti
minID: V8L-R6N
Date: Apr 5th, 2026
Locality: Sioux County, Nebraska, USA (See on Mindat)
Size: 13 x 6 x 17 cm
Weight: 830 g

Description:
Calcite and chalcedony, fluorescent red and green under UV light, respectively. The calcite is between two layers of chalcedony, giving the appearance of a watermelon slice. Usually these are photographed from their side, showing a cross cut of the three layers. In this case, the front chalcedony layer is broken, showing some of the calcite. The appearance of a watermelon rock is lost, but easier to display. The calcite reacts best under midwave UV light, while the chalcedony is quite good under both mid and short wave UV.

Fluorescence under midwave and shortwave UV light.
Fluorescence under midwave and shortwave UV light.
Normal light.
Normal light.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

  • Fluorescence under Midwave (305nm Lamp/Mercury) UV light: Red
Chalcedony (Mindat) (RRUFF)
  • Fluorescence under Midwave (305nm LED) UV light: Green
  • Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Green

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