Mont Saint-Hilaire at CMN – At the Heart of Canada’s Mineral Collection

An astounding 99.9% of the entire volume of our planet’s crust is made up of less than a 100 of the 5,500-plus unique mineral species known to form on Earth. The take-home message: on Earth, mineral diversity is oddly rare! However, diversity is observed at an explosive scale at a handful of specific localities. Situated on Mont Saint-Hilaire about 40 km east of Montreal, the Poudrette (Demix) quarry is one such location. In an area less than 1 km2, an incredible 439 mineral species—25% of all known in Canada—can be found. Of these 439 species, 71 were first discovered here.

An aggregate of prismatic, bright blue carletonite crystals. — Carletonite, one of 71 new mineral species discovered at Mont Saint-Hilaire, QC, Canada (6 x 9 cm, CMNMC 87519). Image: © Gilles Haineault

The reason behind this remarkable diversity is compositional complexity of the alkaline rocks that characterize Mont Saint-Hilaire. Here, mineral species containing more than 40 different chemical elements have been found. Many of these constituent elements—lithium (Li), beryllium (Be), zirconium (Zr), niobium (Nb) and the rare earth elements (REE) among others—are themselves rare in the Earth’s crust. Even after decades of scientific study, many of the geological processes responsible for the creation of Mont Saint-Hilaire over 115 million years ago remain a mystery.

A short-prismatic, orange crystal of rémondite-(Ce). — Rémondite-(Ce), one of more than 60 rare-earth element bearing mineral species found at Mont Saint-Hilaire, QC, Canada (2.5 x 2.5 cm, CMNMC 87425). Image: © Gilles Haineault

In October 2020, the Canadian Museum of Nature proudly announced the acquisition of the Gilles Haineault – Mont Saint-Hilaire Collection. Undoubtedly, this is the most comprehensive collection of Mont Saint-Hilaire material in existence.

A lustrous, rosette-like aggregate of brown-beige catapleiite crystals on a grey matrix — Catapleiite, en matrix with associated microcline, aegirine and natrolite. Mont Saint-Hilaire, QC, Canada. Arguably the centrepiece of the Collection, the catapleiite in this impressive specimen is considered the best known. The whole specimen – 26 x 16 cm, catapleiite crystals – 15 x 9 cm (CMNMC 87521). Image: © Gilles Haineault

For over 30 years, G. Haineault was given unprecedented access to freshly exposed quarry material. His incredible skill, patience and dedication have resulted in a collection totaling over 8,000 pieces.

A macro photo of several prismatic, yellow crystals of haineaultite. — Haineaultite, a mineral named in honour of Gilles Haineault in 2004 by mineralogists A. MacDonald (Laurentian University) and G. Chao (Carleton University). Mont Saint-Hilaire, QC, Canada (field of view 3 mm, CMNMC 87634). Image: © Gilles Haineault

At the Museum, many of these newly acquired specimens will serve as crucial research tools, helping us to better understand the geochemical complexity that makes our Earth such a unique planet in the solar system.

Many specimens in this Collection are also of unparalleled physical beauty, exhibiting incredible optical qualities (colour and clarity), atomically perfect crystal shapes and forms, and exemplary crystal size. Recently, 1,160 of the top specimens were acknowledged by the Canadian Cultural Property Export Review Board (CCPERB) as veritable Canadian treasures, taking their rightful place alongside objects like Group of Seven masterpieces and Glenn Gould’s infamous Steinway. Integral to Canada’s

cultural identity, they are protected from sale or export and will remain discoverable to future generations of researchers and enthusiasts alike.