Locally Mined Beauty: Grossular Garnet from Quebec’s Historic Jeffrey Mine

If you’ve ever dreamed of owning a gemstone that’s not only beautiful but also deeply rooted in Canadian soil, let me introduce you to one of our nation’s hidden treasures: grossular garnet from the Jeffrey Mine in Quebec.

As a Canadian gem cutter, I recently had the pleasure of faceting a round grossular garnet sourced from old stock – material that was mined years ago from the now closed Jeffrey Mine in Asbestos, Quebec. The result is not just a brilliant gemstone, but a piece of Canadian geological and industrial history.

Hessonite garnet

Image taken by Rob Lavinsky of iRocks.com

What Is Grossular Garnet?

Grossular is a member of the garnet family, most often recognized for its vivid green, honey-yellow, or minty hues. While garnets are commonly thought of as red, grossular offers a much more varied and eye-catching palette. The yellowish-orange variety, called hessonite, is rare in Canada and is prized for its colour, brightness, and natural sparkle.

Jeffrey Mine hessonite garnets are known for their distinctive striations, which are fine lines or grooves on the crystal faces, adding to their aesthetic appeal. These striations are a classic feature of the hessonite garnets found in Jeffrey Mine. 

A Gemstone Born in Quebec

The Jeffrey Mine – once the world’s largest asbestos mine – officially opened in 1879. It was a geological wonder, known not only for asbestos but also for producing exceptional crystals of grossular garnet, vesuvianite, and other rare minerals. Located in the Eastern Townships, this mine offered a glimpse into Canada’s rich and often overlooked gemological heritage.

Although the mine ceased operations in 2001, and then was formally decommissioned in 2012 , small amounts of facet-grade grossular garnet still exist in the hands of collectors, miners, and gem cutters. This means that gemstones from the Jeffrey Mine are becoming increasingly rare, making them all the more valuable and meaningful – especially for Canadians interested in locally sourced faceted gemstones, which are almost non-existent on the market.

Jeffrey Mine, Quebec

Canada’s biggest power shovel loading an ore train with asbestos at the Jeffrey Mine, Johns-Manville Co., Asbestos, Quebec, June 1944.

Faceting a Piece of Canadian History

The grossular garnet I recently faceted came from vintage rough material. It’s a bright, golden yellowish-peach, with the classic Jeffrey Mine hessonite striations.

Every gemstone tells a story, and this one speaks of Canadian earth, heritage, and skill. It’s a reminder that not all fine gemstones need to be imported – some of the world’s most beautiful minerals can be found right here at home.

How to Find Jeffrey Mine Garnets Today

Since the mine is no longer in operation, finding facet-grade Jeffrey Mine grossular isn’t easy – but it’s not impossible. You can:

• Check with Canadian gem shows and mineral collectors

• Look for old stock from lapidaries or rockhounds

A Final Word

Canada may not be as well-known as Sri Lanka or Brazil in the gemstone world, but we hold some stunning secrets beneath our soil. This grossular garnet from Quebec’s Jeffrey Mine is a brilliant reminder that local can be luxurious, and that beauty can be born just a few provinces away.

Whether you’re a collector, a jewelry lover, or someone who values sustainable and meaningful sourcing, consider looking local. The next gem in your collection could be Canadian.