1515Art Posted April 23, 2020 Share Posted April 23, 2020 Went out to gold basin yesterday for a long day of hunting with the 7000 For meteorites, gold and collecting hot rocks, I saved about 30 #’s of interesting (to me) for crushing at home in a new cast iron 1qt dolly pot from Royal Mfg I just ordered. Two of the specimens I have question about the first I’m wondering if this is hydrothermal pyrite in quartz like matrix that may in fact be other than quartz? the other hit very hard on the 7000 is only very very slightly magnetic looks like a densely packed conglomerate with very small quartz pebbles cemented in the matrix and lots of mineralization weighing almost 13 #’s, is this worth the time to crush and pan? Link to comment Share on other sites More sharing options...
1515Art Posted April 24, 2020 Author Share Posted April 24, 2020 The what I thought was a conglomerate doing more research I’m thinking now is probably iron ore, a typical cut off saw blade won’t touch it, nor will my belt sander. A diamond cut off wheel cuts fairly easily spitting small fragments as it cuts, smashing it with a 3# hammer on an anvil chipped off small pieces but so far it’s resistant to breaking I’m going to need a bigger hammer if I want to put the effort into pulverizing and panning? Couple pics under the skin and one of the broken crusty oxidized surface? Link to comment Share on other sites More sharing options...
GB_Amateur Posted April 24, 2020 Share Posted April 24, 2020 16 hours ago, 1515Art said: I’m wondering if this is hydrothermal pyrite in quartz like matrix that may in fact be other than quartz? The color of the metallic luster material doesn't show the yellow tinge of pyrite. Is your photo true color, or does pyrite sometimes not appear yellow? Link to comment Share on other sites More sharing options...
1515Art Posted April 24, 2020 Author Share Posted April 24, 2020 58 minutes ago, GB_Amateur said: The color of the metallic luster material doesn't show the yellow tinge of pyrite. Is your photo true color, or does pyrite sometimes not appear yellow? The color is accurate, I was just going on other pictures found on google and there were pictures of silvery deposits on white matrix they called hydrothermal shock pyrite so without knowing I guessed the pyrite I Have no idea? Link to comment Share on other sites More sharing options...
1515Art Posted April 24, 2020 Author Share Posted April 24, 2020 In looking at more pictures it resembles Sylvanite or possibly calverite but I don’t detect any tinges of yellow in the silvery crystals, it also didn’t hit on the 7000 it was a sun baker I collected this visually. The total weight is 970 grams how much is matrix vs metal telluride although I’m unsure if it’s even a telluride? Link to comment Share on other sites More sharing options...
GB_Amateur Posted April 24, 2020 Share Posted April 24, 2020 Here's a picture of two pieces of calaverite I bought from a Cripple Creek, Colorado miner at a gem and mineral show in Denver. The one that shows gold has been roasted. The Minelab Equinox 800 at 40 kHz single frequency in gold (aka 'prospecting') mode with the 11" coil and gain maxed at 25 gives a decent signal if I basically rub the bottom of the coil over each piece. That is, both pieces sound off independently without noticeable difference. However, even at half an inch the signal pretty much disappears. I should have included something in the picture to show the scale. The smaller piece (non-roasted one) can be almost hidden with a modern USA penny with just the extreme corners showing. Link to comment Share on other sites More sharing options...
1515Art Posted April 24, 2020 Author Share Posted April 24, 2020 22 minutes ago, GB_Amateur said: Here's a picture of two pieces of calaverite I bought from a Cripple Creek, Colorado miner at a gem and mineral show in Denver. The one that shows gold has been roasted. The Minelab Equinox 800 at 40 kHz single frequency in gold (aka 'prospecting') mode with the 11" coil and gain maxed at 25 gives a decent signal if I basically rub the bottom of the coil over each piece. That is, both pieces sound off independently without noticeable difference. However, even at half an inch the signal pretty much disappears. I should have included something in the picture to show the scale. The smaller piece (non-roasted one) can be almost hidden with a modern USA penny with just the extreme corners showing. Big difference after roasting, the pre roast sample could be similar to my piece if the silvery spec in the lower left bottom piece I’m seeing is just that my sample is covered in those tiny bits as well as the clusters and feathery formations on the surface and throughout. How did you go about roasting? I have a small electric ceramic kiln that fires off a computer controller with a firing chamber roughly 18”H x 13”W that will fire up to 2350F I just need to install an electric connection in my garage to fire it. Link to comment Share on other sites More sharing options...
GB_Amateur Posted April 24, 2020 Share Posted April 24, 2020 17 minutes ago, 1515Art said: How did you go about roasting? Actually I didn't. I bought it that way from the miner who did the roasting. Someone here may be able to say how it's done, though. Link to comment Share on other sites More sharing options...
1515Art Posted April 24, 2020 Author Share Posted April 24, 2020 Thanks I appreciate all your help, my guess from more poking scraping and straining the heck out of my eyes the silvery spots at the surface anyway are soft and crumbly and with tweezers I could pull off a tiny mica like silvery flake that seemed brittle? Had a little Dusting of glitter on my desk when I got done I don’t know if dunking it in CLR had any affect? One by one hopefully collecting, smashing and scratching my head eventually leads to more nuggets, 😃. Link to comment Share on other sites More sharing options...
jasong Posted April 26, 2020 Share Posted April 26, 2020 There aren't really any known tellurides in the Gold Basin area that I'm aware of, the first sample is more likely to be feldspar and muscovite. There may be some quartz mixed in there, as pegmatites are common intrusive features in the area. Felsic dikes and sills are one of the main features I associate with nuggets out there. The gold associated with these rock types is often free and visible, does not require roasting. If you find softer pieces that feldspar will scratch, especially if they develop a slight green hue, that is sericite which is an alteration product of the mica, and indicates the pegmatite was in contact with a hydrothermal fluid bearing fracture, a common source of nuggety gold out there and something to look for. The second piece is a piece of ore containing quartz and maybe some calcite, and the shiny bits are probably a sulfide of lead, iron or something of the likes. This type of ore does require roasting after crushing. I've been watching MBMMLLC on Youtube quite a bit during this Covid break, his videos on roasting, smelting and assaying are pretty well done and easy to understand for anyone interested in that whole process. He's showing quite a few different methods and covering a lot of bases that I never heard of. https://www.youtube.com/user/mbmmllc/videos Link to comment Share on other sites More sharing options...
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