Newbie needs help from diamond prospectors, Haven't been able to find someone to positively identify |
Newbie needs help from diamond prospectors, Haven't been able to find someone to positively identify |
Aug 8 2015, 08:07 PM
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#1
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Diggin' In! Group: Members Posts: 16 Joined: 8-August 15 Member No.: 121,288 |
Okay, to start off with, this is my first post, here. I'm not from Colorado, and neither are the minerals I'm asking for help with. I hope that's not a rules violation. To make a long story short I was doing some gold prospecting in NE Illinois. Yes, Illinois. In with my black sands, which turned out to have some gold, but not enough to mess with, I found these:
After doing a little research, they look to be pyrope, I think. Let me know if you disagree. Then I found a few rocks like this: So, I extracted a bunch of the small crystals. Which look like this: A lot of them still have a bit of the host rock still stuck to them, but, as is, I did a Specific Gravity test and came up with between 3.1 and 3.2 with less than lab-grade equipment. I'm working on cleaning them up some more & when completed in a day or so, will redo my SG test. I also did check the SG of the host rock and that came back at 2.5. My guess is that the cleaning will raise SG to 3.5, or so. The way I did my SG test was to weigh out a sample, then put them into a graduated cylinder half full of water to see how much water was displaced. Using water I had a bit of a problem with air bubbles that just were a bear to get rid of. Would it be better to use a light oil when I rerun my test? I've also subjected them to scratch tests up to mohs 8 (beryl). I don't have any corundum to check further, unfortunately. I've also soaked them in strong, hot acids, and also in lye, none of which has any affect on them. The only thing I've done that had an adverse affect was to heat a couple of them over an open, natural gas flame, 'til they were red-hot, which turned them an opaque white. I've taken these to jewelry shops, rock shops, and a lapidary museum. So far, no one has been able to positively identify these crystals. |
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Nov 14 2015, 08:06 PM
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#2
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Observer Group: Members Posts: 2 Joined: 14-November 15 Member No.: 122,179 |
I just happened upon this discussion in the process of searching for information on a related subject. I am a GIA trained Graduate Gemologist and I have a low tech suggestion to offer that I believe would be helpful.
Select one of the smaller specimens and smash it with a hammer. (Wear goggles and do this inside a box that will keep the fragments from flying everywhere.) Due to its cleavage, diamonds break with a characteristic step-like fracture. Many other minerals cleave, but I have never seen any that break with the same appearance as diamond. If the material breaks with a conchoidal (shell-like) fracture, such as glass does, the material is not diamond. So this simple test has the potential of providing a definite negative, but not a conclusive positive. The triangular markings on diamond crystals are called trigons. If those are present, that is a good indication. If you have some small specimens you would like me to examine for you, I would be happy to. Best Regards, (Mr.) Kim Shaffer, G.G. Wichita, Kansas |
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Nov 15 2015, 11:56 AM
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#3
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Rock Bar! Group: Members Posts: 898 Joined: 9-January 14 From: Denver, CO Member No.: 116,265 |
I just happened upon this discussion in the process of searching for information on a related subject. I am a GIA trained Graduate Gemologist and I have a low tech suggestion to offer that I believe would be helpful. Select one of the smaller specimens and smash it with a hammer. (Wear goggles and do this inside a box that will keep the fragments from flying everywhere.) Due to its cleavage, diamonds break with a characteristic step-like fracture. Many other minerals cleave, but I have never seen any that break with the same appearance as diamond. If the material breaks with a conchoidal (shell-like) fracture, such as glass does, the material is not diamond. So this simple test has the potential of providing a definite negative, but not a conclusive positive. The triangular markings on diamond crystals are called trigons. If those are present, that is a good indication. If you have some small specimens you would like me to examine for you, I would be happy to. Best Regards, (Mr.) Kim Shaffer, G.G. Wichita, Kansas Welcome to the forums Kim! Thank you for the useful tips. I have not prospected for diamonds yet, but I hope to give it a try next season. -------------------- |
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