A very rare specimen of donnayite-(Y) covered with yellow alicewilsonite-(YCe) from this great locality - Mont Saint-Hilaire, Quebec, Canada. Donnayite-(Y) is uncommon sodium, calcium, strontium, yttrium carbonate and the best pieces come from this mine. It displays a pseudo-hexagonal crystal. It has a partial yellow crust of alicewilsonite-(YCe), which was known for 40 years as MSH UK33a and was approved as a new species in 2020. The Poudrette Quarry is the only locality where alicewilsonite-(YCe) is found. Some white albite is seen too. For references see the 1990 issue of The Mineralogical Record vol. 21, # 4. Some natural imperfections. On acrylic base.

Superb rarity!