Brightly Fluorescent Diopside in Calcite, Fort Ann, New York

Contributed by: Chris Clemens
Date: Apr 25th, 2026
Locality: Fort Ann, Washington County, New York, USA (See on Mindat)
Size: 7.1 x 4.52 x 7.43 cm
Weight: 241 g

Description:
This is a spectacular fluorescent diopside specimen that rivals most Franklin material for brightness. Collected in 1995 from a roadcut along US Rt. 4 in Fort Ann, New York, this piece contains brightly fluorescent grains of diopside in a calcite groundmass with non-fluorescent pyrite. What makes this specimen so unusual is the high content of diopside compared to similar specimens obtained from this location. Under shortwave UV the diopside shows a very bright blue/white response, and the calcite glows a dim blue.

Originally posted by Chris Clemens on Nature's Rainbows in 2016.

Fluorescence under shortwave UV light.

Normal light.

Summary of luminescence responses:

Diopside (Mindat) (RRUFF)

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