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July-August 2013

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Letters

GOLDEN INVITATION

The Colorado School of Mines Geology Museum (CSMGM) invites all those in town for the Denver Gem and Mineral Show (13–15 September) to attend our annual open house on 11 September 2013, 6–9 P.M., the Wednesday evening preceding the show. Come look at our displays and visit with our Museum Advisory Council members, student aides, volunteers, and Friends of the CSMGM, and also browse our gift shop. Again this year we are encouraging mineral dealers and corporations to help sponsor the event, for which they will receive special recognition in return for their kindness. (Please phone for details.)

Every year we strive to change 20 percent of our exhibits to make our museum more exciting for returning guests. This year will be no exception, so be prepared for some spectacular surprises. As always, our gala offers free hors d'oeuvres and a cash bar. The melodious Colorado School of Mines String Quartet will be performing. We hope to see you there.

ROSE QUARTZ

Having been a collector of high-quality, well-crystallized rose quartz for the past twenty-five years, I must compliment Janet Clifford on her outstanding and informative article on rose quartz in the November/December 2012 Connoisseur's Choice column (pages 530–539). Getting details on the actual mine names, exact locations, distance to towns, and names of districts and municipalities, especially for Minas Gerais, Brazil, was an education and answered many questions I had.

Again, my compliments to her for such an interesting and informative article.

MISLABELED

I notice that the Harris Precht fluorite specimen that appears in two places (pages 3 and 79) in the January/February 2013 issue is mislabeled as to its accessory crystals. They are pyrite instead of sphalerite. My sons and I collected that specimen in a typical oil-containing pocket in the Suever quarry at Delphos, Ohio. The lustrous brown fluorite is often accompanied by similarly well-preserved pyrites of octahedron and more complex habits. Of the numerous such pockets we have collected, I don't remember ever seeing any sphalerite in them, although sphalerite does occur in quite nice small crystals in another layer of the quarry, sometimes associated with bicolored (yellow/purple) fluorite. It is a very nice representative of Ohio fluorites.

Caption: Fluorite with pyrite (not sphalerite) from the Suever quarry, Delphos, Ohio.

CANADIAN QUARTZ

After reading about exotic mineral localities around the world, it's always a treat to be surprised by something found right in one's own backyard, so to speak. The very informative article by Michael Menzies and Si Frazier titled “Unusual Quartz and Chalcedony Pseudomorphs from Canada's Alberta Badlands” (November/December 2012, pages 512–521) made me re-look at my own collection, and I was thrilled with what I found. I have been an avid mineral and fossil collector since I was a kid in the mid-1970s, with my native Alberta badlands as my first (and current) stompin' grounds. I routinely come across quartz microcrystal clusters and various forms of chalcedony, as described by the authors, and have collected many pieces as a byproduct of fossil hunting. However, I was completely unaware of the complex array of crystal habits and their unique geologic history. I found many specimens mislabeled in my own collection but could verify the existence of almost all the habits noted in the article. Not realizing there was a pseudocubic habit for quartz, I had previously chalked up many specimens as being calcite, dolomite, or even barite and have never looked back, until now. I can confirm the existence of these unusual quartzes on ironstone nodules from other localities in Alberta (e.g., near Dinosaur Provincial Park, Brooks, Alberta) and from formations other than those reported in the article, most notably the Belly River Formation (aka Judith River Group). I have been in contact with Dr. Menzies, and we plan to share specimens and locality information to better document this interesting material. Thank you for publishing this “local exotica.”


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