Polylithionite Rosette from Mont Saint-Hilaire, Quebec, Canada
Contributed by: FMS Admin
minID: 3J0-5RM
Date: May 17th, 2026
Locality: Poudrette quarry (De-Mix quarry; Demix quarry; Uni-Mix quarry; Carrière Mont Saint-Hilaire; MSH), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada (See on Mindat)
Size: 3.9 x 1.5 x 4 cm
Description:
While not being of considerable size, this is one of the most aesthetic specimens in my collection. It consists of a well-formed rosette of polylithionite with a misshaped serandite crystal in the middle, with very small leucophanite crystals on its termination.
Under shortwave UV, the polylithionite glows yellow, the leucophanite bright pink (brighter under midwave), and a very small dot of red fluorescing calcite shows up (also best MW but bright SW). Very pretty both under UV and in white light. This cutie is from the last significant find in Mont Saint-Hilaire, the serandite-albite-polylithionite-leucophanite pocket found in 2003. Another specimen I posted, a nice polylithionite-leucophanite-albite-serandite-calcite combo, also comes from this huge pocket.
Originally posted by Frédéric Messier Leroux on Nature's Rainbows in 2021.
Summary of luminescence responses:
Polylithionite (Mindat) (RRUFF)
- Fluorescence under Shortwave (255nm LED) UV light: Yellow
- Fluorescence under Shortwave (255nm LED) UV light: Pink