Steve Herschbach Posted January 6, 2023 Share Posted January 6, 2023 9 hours ago, phrunt said: I put 3 hot rocks in the photo but I must have dug 30 of them, the 6000 loved them and I couldn’t balance them out, normal, difficult, low sensitivity, nothing helped. We have them here. I think they are rhyolite, fine grained, usually some tiny bubbles (hollow spots) and some white bits enclosed in the gray or pinkish mass. Sound exactly like a gold nugget, and no 6000 setting or coil will knock them out. 7000 does not like them either. Luckily, the places I have run into them they are not quite so plentiful as to be more than annoying. If an area was thick with them it would shut you down or force a change in equipment. Rhyolite is high in silica and total alkali metal oxides, and alkali metal oxides can have high conductivity. I'm just winging it on the identification but I think I'm close. Rhyolite varies in appearance depending on the exact composition and how quickly it cooled. Some pictures: 6 3 Link to comment Share on other sites More sharing options...
phrunt Posted January 6, 2023 Author Share Posted January 6, 2023 Thanks, I intended to go in about an hour after dinner once it cooled down but the wife is telling me a thunderstorm is coming so may have to leave it until tomorrow night. I was hoping the DD may help, I’ve struggled with them with the GPZ before in the same general area. I think your rock educated guess maybe correct Steve. Does the Axiom handle them any better? Link to comment Share on other sites More sharing options...
PhaseTech Posted January 6, 2023 Share Posted January 6, 2023 Yep, flyschitt or bits is what I call the really tiny ones. Something around half a gram may occasionally get called a nuggy, especially if it's got a bit of character. 1 Link to comment Share on other sites More sharing options...
Steve Herschbach Posted January 6, 2023 Share Posted January 6, 2023 1 hour ago, phrunt said: Does the Axiom handle them any better? Easily knocks them right out. 4 1 Link to comment Share on other sites More sharing options...
phrunt Posted January 6, 2023 Author Share Posted January 6, 2023 4 minutes ago, Steve Herschbach said: Easily knocks them right out. Awesome Link to comment Share on other sites More sharing options...
Valens Legacy Posted January 6, 2023 Share Posted January 6, 2023 13 hours ago, phrunt said: My first nugget for 2023 Great looking nuggets no matter what someone else says they are. Good luck on many more and stay safe out there on them hills. 1 Link to comment Share on other sites More sharing options...
mn90403 Posted January 6, 2023 Share Posted January 6, 2023 Thanks for the post Simon. I'd be out there after more no matter the weather. Big hat, cool drinks, awning, chairs ... 1 Link to comment Share on other sites More sharing options...
afreakofnature Posted January 6, 2023 Share Posted January 6, 2023 10 hours ago, Steve Herschbach said: We have them here. I think they are rhyolite, fine grained, usually some tiny bubbles (hollow spots) and some white bits enclosed in the gray or pinkish mass. Sound exactly like a gold nugget, and no 6000 setting or coil will knock them out. 7000 does not like them either. Luckily, the places I have run into them they are not quite so plentiful as to be more than annoying. If an area was thick with them it would shut you down or force a change in equipment. Rhyolite is high in silica and total alkali metal oxides, and alkali metal oxides can have high conductivity. I'm just winging it on the identification but I think I'm close. Rhyolite varies in appearance depending on the exact composition and how quickly it cooled. Some pictures: Yes you are correct these are examples of Rhyolite. The ones with the large phenocrysts are called Porphyritic Rhyolite or Rhyolite porphyry. 2 Link to comment Share on other sites More sharing options...
Steve Herschbach Posted January 6, 2023 Share Posted January 6, 2023 9 minutes ago, afreakofnature said: Yes you are correct these are examples of Rhyolite. The ones with the large phenocrysts are called Porphyritic Rhyolite or Rhyolite porphyry. Yes, they definitely are, since they are from the Geology.com site about Rhyolite. I guess I should have noted they are not pictures of the rocks I have so it’s still an open question. The pics were more to help Simon maybe id what his were. I’ll dig my samples out if I get time and confirm what they are, but it’s pretty low priority at the moment. 2 Link to comment Share on other sites More sharing options...
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