Sunday, February 18, 2007

Doubly Terminated Quartz Crystals in Victoria, BC

Interesting article from the Times Colonist in Victoria, BC:

Sure, it looks like a diamond, but don't be fooled
80-million-year-old quartz crystals found on Duncan hilltop appear fancier than they are Sandra McCulloch, Times Colonist
Published: Monday, February 12, 2007

They're as old as dirt, and not worth much more, yet quartz crystals found high on Mount Tzouhalem near Duncan are attracting significant attention from rockhounds.

Development on the 500-metre hill on the north side of Cowichan Bay has unearthed quartz crystals that are about 80 million years old and that look as though they've been hand cut in the same fashion as diamonds.

"They look very similar (to diamonds) if you're not into mineralogy. It can be very difficult to tell the difference," said Brian Grant, a geologist with the provincial government.

The crystals are six-sided and "doubly terminated," meaning they have a sharp pyramid at each end. "It looks like a diamond ... there are several different crystal shapes for diamonds but one of the forms is a double octahedron, which is two little four-sided pyramids."

These types of crystals look so much like diamonds, the most famous ones are called "Herkimer diamonds," after a New York town close to where they were found.

"The thing about the Herkimer diamonds in New York is the quartz tends to be especially clear and sparkly," while the ones found on Mount Tzouhalem are darker in colour, said Michele Heath, former president of the Cowichan Valley Rockhound Club.

Quartz crystals have been found all over the world, and usually form in cavities in rock. "You have silica-rich water that leaches into these cavities and gradually deposits the silicon. If it deposits it slow enough, you get these crystals," Heath explained.

"They're not attached to the wall of the cavity so both ends can form crystal faces. They're laying loose in the cavity rather than being attached to the wall of the hole."

While the mineral basis of these quartz crystals have nothing in common with diamonds, which are carbon-based, Heath says they are often mounted into jewelry because "they look as though they've been hand-cut and the quality of the quartz is really good."

Still, discussion of the naturally formed crystals draws a yawn from most geologists, said Grant.
"For people who have a hobby of collecting rocks and minerals and things like that, yeah, there would be a definite interest in them. Value-wise, they're not particularly rare or expensive to buy."

The crystals are much easier to find than diamonds, added Heath.

"They're often in places accessible to amateur rock-collectors and I think that sort of adds to the hype about it."

© Times Colonist (Victoria) 2007

1 comment:

Heidi said...

I hike Mt.Tzouhalem every day with my friends and dog and every day I find the herkimers, and to say that the New York ones are shinier, that is not true as we have beautiful, shiny ones here also. We have browny, grey ones but a lot of shiny ones. I know some people who would come and dig here and they found gorgeous ones. The person that said they aren't shiny is wrong and maybe should do a study before saying this out loud. Give Mt. Tzouhalem a better story. Just because it isn't New York doesn't mean it isn't great. Duncan's Mt. Tzouhalem deserves a chance. Heidi Mitchell