lordsorril
freely admits to licking rocks
Member since April 2020
Posts: 766
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Post by lordsorril on Jun 10, 2020 3:03:34 GMT -5
I'm new at collecting material for my rock tumblers. I found a big chunk of quartz in a local river bed (MA)--sitting by itself (no other pieces around). Noticed some red patterning--thought it might be neat to tumble so I dragged it to my car and took it home and smashed it up for tumbling material. Afterwards I noted some gold colored veins running throughout (example below). Can someone confirm if this is gold or is it more likely that it is some form of pyrite or different mineral based on the matrix? The river is not known to contain any gold.
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Post by rmf on Jun 10, 2020 5:17:43 GMT -5
It is hard to say from the image but above the right oval there is what looks to be iridescent Iron staining. Probably from organic acids working on pyrite. My guess is you are seeing a thin coat of Iron on those areas. Native gold is a richer color. Take your rock to a coin shop and ask to see a Canadian Maple Leaf (.9999 fine gold) this is more pure than in nature but the color is what you are looking for. Natural gold will be about the same color. I think you will notice that the staining on the rock is the "wrong color" for gold.
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dreamrocks
freely admits to licking rocks
I got lucky this morning and was able to post this no others since
Member since November 2018
Posts: 888
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Post by dreamrocks on Jun 10, 2020 5:45:25 GMT -5
Another simple test is take a common pin and see if you can push it into those areas in question, mica will flake off or chip out, the pin won’t do anything to pyrite because it’s much harder then gold. The pin test will leave a pin hole or stick into it that area just like amber A knife will also scratch it think of it as your testing a piece of lead you scratch a lead sinker (fishing weight) it will leave a fresh scratch and will not flake or chip like mica does I have seen gold in quartz and it was milky quartz and Snow White On the other hand it does look like some kind of reaction from the Iron or staining in the right oval of some sort
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lordsorril
freely admits to licking rocks
Member since April 2020
Posts: 766
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Post by lordsorril on Jun 10, 2020 7:01:57 GMT -5
Thank you both for the info! I think it is pyrite. It doesn't flake off and a pin doesn't do anything to this stuff. I thought the adjacent red iron deposits were too convenient and the color of the host quartz did not match what I expected for gold.
I had shown my girlfriend theses rocks yesterday and she had taken them from me and carefully placed them aside one-by-one until I could confirm their identity (which was funny since I had just hit them with a sledgehammer...). After reading your posts: She took the rocks this morning and then angrily dumped them into my 'tumble material' bin. Thanks again!
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