Canadian Rockhound: Diamond

Diamond. Photo courtesy of Amethyst Gallery.

Diamond
By Doug Miller

Diamond, C, has been found in a swarm of kimberlite pipes near Forte a la Corne, northeast of Prince Albert. Crystals are isometric and predominatly octahedral. Diamond is one of the most highly prized gemstones due to its hardness (hardest known material) and its optical properties. The high refractive index (2.417) and high dispersion (0.044) make the faceted stones sparkle and flash with rainbows of light.

Exploration of these kimberlite pipes is being undertaken by several companies. The largest is a joint venture between Kensington Resources (30%), Uranerz Exploration and Mining (10%), Cameco Corporation (30%) and Monopros Limited (30%), a wholly owned subsidiary of DeBeers.

The Fort a la Corne Diamond Project covers 25,488 hectares of claims and includes 71 known kimberlite pipes. Thirty-four pipes have been shown to contain macrodiamonds (diamonds bigger than 1 mm). The largest diamonds recovered to date are 0.985 and 0.275 carats. The smaller macrodiamond is clear and white and may be a fragment of a larger stone.

The geology of these pipes is unique in the world as they are covered by a thick sedimentary layer deposited by an ancient inland sea. This layer has left the full kimberlite volcanoes intact. Usually, the wide volcanic crater and the top of the kimberlite pipe are eroded away, leaving only the pipe. In this swarm, single bodies up to 1.6 kilometers in diameter have been found, containing an estimated 1 billion tonnes of kimberlite. If the diamonds are found in quantities of only 0.5 ct/tonne of kimberlite, this would amount to a total reserve of 100 tonnes of diamond!

On going exploration and evaluation of the kimberlite pipes will determine the potential value of these properties and their future as viable mines. Unfortunately, specimens of Saskatchewan diamonds will not likely be made available to mineral collectors, except as faceted stones purchased through jewelry stores.

Additional information may be found at the Kensington Minerals website at www.kensington-resources.com.

This article may not be copied, distributed or reprinted in any form without the author's permission. To contact the author, please use the e-mail address provided. If you are unable to contact the author, please contact the Canadian Rockhound. Authorized reprints must acknowledge the author, original source and the Canadian Rockhound, and include the website URL address of the Canadian Rockhound.

The preceding article was first published in the May 1997 newsletter of the Saskatoon Lapidary & Mineral Club. Reprinted with permission. Reprinted in the Canadian Rockhound with permission from the author.