Orthoclase var. Andularia - Shigar Valley, Pakistan

Contributed by: Mark Cole
Date: Apr 3rd, 2026
Locality: Shigar Valley, Shigar District, Gilgit-Baltistan, Pakistan (See on Mindat)

Description:
Apparently, both distinct colors are orthoclase with different activators.

Originally posted by Mark Cole on Nature's Rainbows in 2016.

Fluorescence under shortwave UV light.

Normal light.

Normal light. Specimen size image compared to a US dollar bill.

Summary of luminescence responses:

Feldspar (Mindat) (RRUFF)

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