Hydrodresserite

The specimen features acicular balls of hydrodresserite formed on top of a druse of dawsonit, collected from the type locality. These colourless spherical crystal aggregates are present within vugs of the Francon metamorphosed limestone, near the contact zone of an alkalic dawsonite-rich silicocarbonatite sill, and are associated with dresserite. On the specimen this rare mineral is accompanied by dawsonite (possibly celestine), quartz, and weloganite.

Named as a new species in 1977, hydrodresserite is unstable under most atmospheric conditions and dehydrates to form dresserite. The name reflects this composition and reaction.

Collected by Dr. Tarassoff at the Francon Quarry in central Montreal, this location ceased operations in 1981 and will never reopen, making specimens from this site particularly rare and valuable to collectors.

This specimen comes from the collection of Dr. Peter Tarassoff, a prominent figure in mineralogy, particularly known for his work at Mont Saint-Hilaire (MSH). His diligent collecting and examination efforts have led him to be the first to identify at least 35 species and discover 12 new species, not only at MSH but also at other alkaline localities. Dubbed the "Dean" of Mont Saint-Hilaire collectors, Peter was honoured with the naming of the new species petarasite in 1980. He has authored or co-authored numerous mineralogical articles and has been a member of the Mineralogical Association of Canada since 1964 and the Mineralogical Society of America for over 30 years. Additionally, Peter has volunteered at the Redpath Museum for the past 21 years. In recognition of his significant contributions to mineralogy, Peter was awarded the 2017 Pinch Medal by the Mineralogical Association of Canada.

Peter's dedication to systematic collecting, curating his collection, and maintaining an archive of detailed historical and scientific information has greatly benefited the mineral sciences community both in Canada and globally. All specimens from this collection come with the original P. Tarassoff collection label.