Sodalite

specimen number:
9302326

location:
Poudrette Quarry, Mt. St Hilaire, Quebec, Canada

description:

Choice lustrous translucent blue crystals of sodalite on matrix. A fine thumbnail for the species, especially for this classic locality.

The Poudrette quarry, located on Mont Saint-Hilaire in Rouville County, Quebec, Canada, is an internationally significant mineral locality celebrated for its extraordinary alkaline mineral diversity. Geologically, the site is situated within an igneous complex that forms part of the Cretaceous Monteregian Hills petrographic province, specifically exposing a multi-phase alkaline intrusion composed of syenites, nepheline syenites, and agpaitic pegmatites. Hydrothermal alteration of these highly differentiated, volatile-rich magmas produced hundreds of rare mineral species, many unique to this single locality, within open pockets, breccias, and xenoliths. Industrial quarrying for crushed stone and concrete aggregate began at the site in 1959 under the Uni-Mix company before ownership transferred to the Poudrette family in the 1970s. Commercial quarrying and active mineral specimen extraction operated continuously for decades until operations ceased and the site was officially closed in December 2007, later becoming incorporated into a nature conservation area.

Sodalite is a sodium aluminum silicate carbonate mineral that serves as a principal member of the feldspathoid group. Geologically, it forms almost exclusively in silica-undersaturated igneous environments, crystallizing within nepheline syenites, phonolites, pegmatites, and associated metasomatic rocks where silica levels were too low to permit the formation of standard feldspars. The mineral is widely recognized for its intense royal blue coloration, though it can also occur as white, gray, yellow, or pink masses, and it often exhibits a dull to vitreous luster alongside a strong orange-red fluorescence under ultraviolet light.

Questions about this specimen?
Send an email or call us: 314-341-1811.