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Posted in response to Help with identification from Bob Fischer on July 29, 2008 at 08:52:59:

Re: Help with identification

Hello Bob.

Gold is usually associated with quartz, not often found in a dark colored rock. However . . .the "gold" colored mineral could be a lot of things, most notably pyrite or chalcopyrite, although gold is a possibility. Can you try to scratch it with the tip of a knife blade? If it is gold, it will scratch easily, and the scratch will be gold colored. If pyrite, it will not scratch - the pyrite is harder than a knife blade. Chalcopyrite will scratch, but the mark most likely will appear to be black.

If you can rub a point of the gold material on a streak plate (or the white back of a bathroom tile, or the unglazed bottom rim of a dinner plate) gold will give a gold colored streak, while pyrite and chalcopyrite will give a black streak.

From Don Peck - July 30, 2008 at 08:36:02

Message: 66803

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Bob Keller