Fluorescent Chalcanthite with Antlerite, Brochantite and Shungite(1) - Dongchuan, China

Contributed by: FMS Admin
Date: Mar 20th, 2026
Locality: Dongchuan District, Kunming, Yunnan, China (See on Mindat)
Size: 2.4 x 1.8 x 3.8 cm

Description:
An unusual find in Dec 2021, hard to say to be beautiful but strange enough indeed. As chalcanthite is a simple copper sulfate mineral, there are many famous localities for it like AZ of US or copper mining area of Poland, in China, Qinglong County is also a famous locality, but we never heard if any chalcanthite glows.
Cu(II) is a common quencher as none of Cu(II) minerals glows if I remember well (different from Cu(II), Cu(I) is usually an activator, e.g. marshite). But these chalcanthites does, perhaps some antlerites also.

The identification of chalcanthite and antlerite were confirmed by Raman analysis (see below).

To figure out what is causing fluorescence, we did some further work:
Geiger counter gives about 0.45 ?Sv/h when the Geiger tube put closed to a 8 cm sample, so, it\'s obvious radioactive. SEM-EDS result shows it contains minor Uranium. Also confirms evansite, strictly speaking, it confirms the yellowish green part as an Aluminum phosphate mineral.

EDS gives results as both evansite and chalcanthite (also antlerite perhaps) contains about 0.5 wt% of Uranium, but as SEM-EDS is semi-quantitative test, the content is for reference only.

Emission under 325 nm illumination also gives very typical spectrum that show its fluorescence is caused by uranyl ions (UO₂²⁺), peaks at 498 nm, 519 nm, 542 nm, 567 nm and 597 nm are all classified as UO₂²⁺.

Originally posted by ??? / Hercule Shen on Nature's Rainbows in 2016.

Fluorescence under shortwave UV light. (275nm LED)

Normal light.

Fluorescence under longwave UV light. Closeup 4.46mm FOV

Normal light. Closeup 4.46mm FOV. Blue to light blue - Chalcanthite mixed with antlerite.

Raman spectrum of analyzed chalcanthite

Raman spectrum of analyzed antlerite

EDS spectrum of chalcanthite

EDS spectrum of evansite. EDS gives results as both evansite and chalcanthite (also antlerite perhaps) contains about 0.5 wt% of Uranium, but as SEM-EDS is semi-quantitative test, the content is for reference only.

Emission spectrum of Chalcanthite (325 nm laser illumination)

Summary of luminescence responses:

Chalcanthite (Mindat) (RRUFF)

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