More Minerals

I celebrated my 48th birthday a little over a week ago. I got a package from Jeff Shallit, whose avocation is minerals. Diane and I have met up before with Jeff and his family in the desert southwest, a destination he enjoys particularly for the opportunity to apply geological knowledge and find minerals for himself. Last fall, I accompanied Jeff to a mineral and gem show in Detroit. I had expressed some interest in a couple of types of minerals, and Jeff kindly sent along a couple of samples.

First up is a piece of pyrite, FeS2. This one comes from Navajun, La Rioja Province, Spain. It is a cube, 19.03×19.20×19.31 mm in size. (Electronic readout calipers are cool.) The surfaces are almost mirror-like, and it is somewhat challenging to show any surface texture on the pyrite at all.

wre 8404 ws

And the second is a sample of fluorite, this one from the Rogerley Mine, Frosterley, County Durham, England.

wre 8405 ws

But the real attraction of fluorite isn’t evident until you hit it with ultraviolet light. I took apart a UV light keychain LED bob and a cheap Garrity LED flashlight, and replaced the Garrity white LED with the UV LED from the keychain bob. (Actually, I’ve brought the leads out to a two-place screw-in terminal. I can swap out LEDs for the light of choice.) This gives me a handy UV source I can use in close-ups.

Fluorite with UV

The photo setup is based on a copy stand I made from an old, cheap enlarger. I got rid of the head and simply use the attachment point to mount my camera. The background is a sheet of coarse-grit sandpaper glued down on mounting board. I tilted the whole thing to take the pyrite shot, since with everything flat one sees only two faces on the cube from directly above. The camera is a Nikon D2Xs, and the lens is my old Micro-Nikkor 105mm f/2.8 AIS manual-focus lens. I was shooting at 100 ISO, and given the mixed lighting, the exposure was several seconds at a small f-stop.

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Wesley R. Elsberry

Falconer. Interdisciplinary researcher: biology and computer science. Photographer. Husband. Christian. Activist.

One thought on “More Minerals

  • 2011/02/10 at 2:28 am
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    I work for the pyrite mine in Navajun, La Rioja, Spain and I have photos of the mine, the place is great and Pedro, the owner, is a great person. He goes to Tucson every year.

    Bye

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