Hackmanite, Scapolite, Johachidolite, Feldspar, etc. - Myanmar

Contributed by: FMS Admin
minID: UVC-L5N
Date: May 13th, 2026
Locality: Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar (See on Mindat)
Size: 6.1 x 3.3 x 7.8 cm
Weight: 121 g

Description:
Shown here is a very nice specimen of super deeply tenebrescent sodalite var. hackmanite, from the Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar.

Hackmanite from Myanmar is incredibly hard to find nowadays, especially as rough, uncut mineral specimens; also, it's usually very expensive. So, for this reason alone, I highly treasure this specimen, which I consider myself very lucky to have in my collection. But what also makes it very valuable is how deeply tenebrescent it is; it changes color upon exposure to all UV wavelengths, very quickly. And the fact that quite a generous amount of the rare mineral johachidolite is associated with it. Yellow fluorescing scapolite is also present. Some feldspar (adularia) associated with those minerals fluoresces light blue under longwave UV; it could be assumed that the blue is visible light being reflected from the UV source, but it is actual fluorescence, which I confirmed by placing a piece of UV blocking polycarbonate between the UV light and the specimen. Interestingly, the hackmanite shows small areas of drastically increased fluorescence around grains of uranothorianite.

Under longwave UV, the hackmanite fluoresces bright orange; the scapolite fluoresces bright yellow, the adularia fluoresces light blue. Under midwave UV, the hackmanite switches to blue, white, yellowish and reddish hues. Comparable colors show up under shortwave, with some differences.

Originally posted by Frédéric Messier Leroux on Nature's Rainbows in 2024.