Ronpetersonite

The Ba analogue of stolzite and scheelite. Second (species-defining) Ba-W mineral after uranotungstite.

The grains weakly fluoresce blue-white under 312 nm short wave UV.

"According to Mary Macquistan (personal communication):
The fluorescent properties of ronpetersonite were difficult to determine as the mineral was primarily identified and described in thin section. No fluorescence in the thin section was observed but this is likely due to the fact that the material was so fine grained and only 30 um thick. Weak fluorescence at 312 nm was identified on a single crystal mount, but the small size of the grain presence of epoxy may have affected this result. The thin section chips corresponding to the described grains did not contain fluorescent grains that would correspond to ronpetersonite (some response by cymrite and witherite was observed)."

Further by Mary Macquistan: "However, a hand sample from the Gun occurrence with the same mineral assemblage as the type grains has abundant fine-grained blue-white fluorescent grains under 254 nm UV that do not respond/fluoresce under 365 nm UV (they are transparent and colourless under white light)..... This result is consistent with the responses of synthetic scheelite-structure BaWO4 in previous studies ... which show excitation wavelengths of 230 nm and 270-305 nm cause the material to emit spectra in the blue wavelength range. The blue emission from the scheelite tungstate crystals is known to be due to radiative transitions within (WO4)2- molecular complexes. It is therefore highly likely that ronpetersonite is fluorescent under short wave UV."

A concluding comment from Mary Macquistan: "It is likely ronpetersonite fluoresces blue-white under short wave UV but this property was not well described on the type grains used to characterize the mineral. Support from literature on its synthetic counterpart is considered for this interpretation."