NevadaBill
fully equipped rock polisher
Member since January 2019
Posts: 1,332
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Post by NevadaBill on Mar 18, 2019 10:05:38 GMT -5
I posted this rock once before. It was uncut at the time, and looked like this: An RTH member mentioned that it looked a lot like Limestone. I would just be interested in knowing if it still is some Limestone, or perhaps something else? Here is what it looked like cut open: Both colors on the inside are a bit different than the outside layer. And a bit harder. It looks like it was formed as a ball or egg shape. This is less than a 6 on the hardness scale though.
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Post by MsAli on Mar 18, 2019 13:24:58 GMT -5
No idea but it reminds me of a Bahia agate
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Post by fernwood on Mar 18, 2019 13:48:56 GMT -5
Concretion? The limestone might have formed around a fossil or another rock?
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zarguy
fully equipped rock polisher
Cedar City, Utah - rockhound heaven!
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Post by zarguy on Mar 18, 2019 13:56:02 GMT -5
Looks somewhat like Royal Imperial Jasper from Mexico. Lynn
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Mar 18, 2019 14:31:00 GMT -5
Looks somewhat like Royal Imperial Jasper from Mexico. I agree, minus the "Royal" bit. Not sure who invented the "Royal" moniker 10-15 years ago, but that doesn't add anything to the ID, and doesn't even make sense (royal refers to a king, queen and family; imperial refers to an emperor, empress and family - Mexico has only produced emperors since its independence).
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Post by vegasjames on Mar 18, 2019 15:10:22 GMT -5
Try some acid on the outside and see if it fizzes. Limestone often forms around silicates.
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Post by rockjunquie on Mar 18, 2019 15:19:18 GMT -5
I'm thinking imperial jasper, too. The colors are right and if I remember right, they have chalky white skins.
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NevadaBill
fully equipped rock polisher
Member since January 2019
Posts: 1,332
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Post by NevadaBill on Mar 18, 2019 18:57:38 GMT -5
Concretion? The limestone might have formed around a fossil or another rock? I looked up "Concretion". It does kind of look like one rock forming around another. In this case, there are 3 distinct color layers. The outer layer being the softest.
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fishnpinball
Cave Dweller
So much to learn, so little time
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Post by fishnpinball on Mar 18, 2019 19:01:17 GMT -5
The inside does appear to be an imperial jasper. is the inside harder as around a 7?
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NevadaBill
fully equipped rock polisher
Member since January 2019
Posts: 1,332
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Post by NevadaBill on Mar 18, 2019 19:01:33 GMT -5
Looks somewhat like Royal Imperial Jasper from Mexico. Lynn Interesting. I looked up "Royal Imperial Jasper", and my rock does have some similar patterns to that. Although it is clearly not as complex or colorful as some of the Images that came up. Maybe call mine "Ghetto Imperial Jasper"?. Maybe I should save him and make a cab from him some day!
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NevadaBill
fully equipped rock polisher
Member since January 2019
Posts: 1,332
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Post by NevadaBill on Mar 18, 2019 19:03:14 GMT -5
Looks somewhat like Royal Imperial Jasper from Mexico. I agree, minus the "Royal" bit. Not sure who invented the "Royal" moniker 10-15 years ago, but that doesn't add anything to the ID, and doesn't even make sense (royal refers to a king, queen and family; imperial refers to an emperor, empress and family - Mexico has only produced emperors since its independence). Haha! Jynx! Two minds thinking alike on this one. I also don't think mine looks very "Royal". More like "Rotton Egg Jasper"!
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NevadaBill
fully equipped rock polisher
Member since January 2019
Posts: 1,332
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Post by NevadaBill on Mar 18, 2019 19:05:18 GMT -5
Try some acid on the outside and see if it fizzes. Limestone often forms around silicates. Good idea James. I am not familiar with Acids though. I do have a piece I can test with. Is this something I can buy locally or through the Net? If so, what would be the Acid name? Thank you in advance.
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NevadaBill
fully equipped rock polisher
Member since January 2019
Posts: 1,332
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Post by NevadaBill on Mar 18, 2019 19:13:48 GMT -5
The inside does appear to be an imperial jasper. is the inside harder as around a 7? You know what Norm, I don't have much more than a good sharp knife to test this with. And actually, I gave you guys a false read earlier. I can only scratch the 3rd layer from the inside with a knife. The innermost layer, and darker layer outside of it cannot be scratched. I can't leave a mark on it. But the 3rd layer from the inside can be. There is actually a 4th layer on the outside, but it is very very soft and could be whittled off with a knife.
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Post by hummingbirdstones on Mar 18, 2019 21:34:22 GMT -5
Bill, you can use vinegar for the acid test.
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fuss
spending too much on rocks
Member since October 2018
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Post by fuss on Mar 19, 2019 10:16:23 GMT -5
Chert nodule with outer layer probably chalk. Nice one.
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Sabre52
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Me and my gal, Rosie
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Post by Sabre52 on Mar 19, 2019 15:41:27 GMT -5
I'd say a chert nodule too. Round here the limestone is full of chert nodules that have a limestone rind on the outside. If chert it should be very hard on the inside....Mel
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Post by vegasjames on Mar 19, 2019 16:16:23 GMT -5
Try some acid on the outside and see if it fizzes. Limestone often forms around silicates. Good idea James. I am not familiar with Acids though. I do have a piece I can test with. Is this something I can buy locally or through the Net? If so, what would be the Acid name? Thank you in advance. I use muriatic acid ("pool acid", hydrochloric acid) since I keep a lot of it on hand for cleaning up fossils in limestone and calcite and dolomite rocks as well as experiments. I picked up two gallons of a concentrated acid at the pool store fro about $7.
If calcite or limestone you can also use vinegar. Dolomite is not as reactive.
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RWA3006
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Member since March 2009
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Post by RWA3006 on Mar 19, 2019 20:42:38 GMT -5
Chert nodule with outer layer probably chalk. Nice one. This.
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mjflinty
spending too much on rocks
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Post by mjflinty on Mar 20, 2019 7:44:17 GMT -5
Looks like a chert nodule to this flintknapper ;-)
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NevadaBill
fully equipped rock polisher
Member since January 2019
Posts: 1,332
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Post by NevadaBill on Mar 20, 2019 10:02:46 GMT -5
Bill, you can use vinegar for the acid test. Thanks Robin. I have some vinegar. I will try putting one half in vinegar to see if there is a reaction.
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