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March-April 2011

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Letters

TETRAHEDRITE ADDITION

While perusing my recent Connoisseur's Choice column on tetrahedrite (November/December 2010), I noted with chagrin that I failed to mention a locality I know some of your readers may take me to task for. That locality is Dalnegorsk, Primorskiy Kray, Far Eastern region, Russia. Tetrahedrite from Dalnegorsk occurs normally as grains disseminated in matrix, but it can also occur as crystals to 3 cm on edge, some with corroded faces and others with a coating of chalcopyrite. As noted in V. V. Moroshkin and N. I. Frishman (2001. Dalnegorsk: Notes on mineralogy. Mineralogical Almanac 4:79), the Serebryanaya tetrahedrite vein is silver rich. Going over my show notes from past years, I also note that a Czech mineral consortium had a specimen of Dalnegorsk tetrahedrite for sale that was associated with sphalerite and minor quartz. There may be other localities that some of your readers will call me on, but I felt that the omission of Dalnegorsk was egregious enough to merit my writing this note to correct the record.

Paul W. Pohwat
Department of Mineral Sciences, National Museum of Natural History, (Smithsonian Institution), Washington. DC

CREEDE KUDOS

Thank you for publishing Tom Rosemeyer's article on Creede (September/October 2010) with all of the support material in the accompanying articles on the minerals of the region and support institutions presenting the minerals of Colorado to the general public.

Although we live on and love the Keweenaw Peninsula with its mining history, since the 1970s our second home has been the San Juans. This part of Colorado has seen many changes, but it has remained true to its mining heritage.

Tom's article, with its gorgeous specimen photos and historic vistas, gave a wonderful picture of Creede. As usual with Tom's presentations, whether on Keweenaw or Colorado mineralogy and historical documentation, he culled the pertinent data and yet presented a comprehensive picture of the subject locality. The old saying, “You can't understand today if you don't know how we got here,” is aptly proven by Tom's inclusion of the historical time-line. Such a complex history—usual in a mining district with many transfers of power and money—was presented so all could follow the story and be content if they read no further. Yet the references were plentiful and accessible to provide further reading.

A special note of thanks is extended to the people who opened their collections providing accompanying photo documentation on the mineralogy: Dan Behnke, Dave Bunk, Benji Kuehling, Phil MCollum, and Tom himself; they deserve our gratitude for sharing their wonderful mineral specimens. Beautifully photographed with exquisite color reproduction in the published article, Creede's riches jumped off the pages.

Thanks also go to Rocks & Minerals for allocating such a large chunk of the issue to present a complete picture. We have commented on this before: Rocks & Minerals gives its articles the space needed to tell the story, and that is part of what keeps us looking forward to each issue.

Steve Whelan and Sandi Whelan
Calumet, Michigan

Tom Rosemeyer did a very nice job on the Creede, Colorado, mining area in the September/October 2010 issue. Although the photos were excellent, I did not see a picture of the darkest colored Amethyst vein material from the Commodore mine showing multiple stages of crystal growth.

I thought readers might like to see the enclosed photo of a polished cross section of vein material showing “phantom” amethyst crystals, with each growth episode separated by a thin white quartz overgrowth. There are at least twenty different episodes of amethyst growth on the piece.

Richard Tripp
Denver, Colorado

Editor's note: There is a polished slab of the Amethyst vein material shown in the article as figure 42 on page 410 of the Creede article. However, as Mr. Tripp mentioned, the amethyst is not as darkly colored as that in the photo he supplied.

Caption: Polished amethyst, 19 × 23 cm, from the Commodore mine, Creede, Colorado. Richard Tripp specimen and photo.

Caption: Polished amethyst, 19 × 23 cm, from the Commodore mine, Creede, Colorado. Richard Tripp specimen and photo.

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