Ruby from Jegdalek, Afghanistan
Contributed by: Michael Crawford
Date: Jul 24th, 2025
Locality: Jegdalek ruby deposit, Surobi District, Kabul, Afghanistan (See on Mindat)
Size: 4 x 5 cm
Description:
Bright red ruby (Al2O3) crystals in a marble matrix from the Jegdalek Ruby Deposit, Surobi District, Kabul, Afghanistan. The crystals are incomplete hexagonal prisms. The crystals fluoresce bright red under longwave UV light. The red fluorescence is dimmer under midwave and shortwave light. Chromium (Cr3+) replacing aluminum causes the red daylight color as well as the strong red fluorescence.
The longwave emission spectrum exhibits the distinctive spikes characteristic of ruby. There is a single peak at 692 nm that is significantly brighter than peaks on both sides of this main peak.
Summary of luminescence responses:
Corundum var. Ruby (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Red
- Fluorescence under Midwave (305nm LED) UV light: Red
- Fluorescence under Shortwave (255nm LED) UV light: Red