jamesp
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Post by jamesp on Jan 19, 2016 2:13:11 GMT -5
Looks like oolitic jasper from NW Georgia. but it does not have 3.0 sg
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br347213
starting to spend too much on rocks
Henderson, NV
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Post by br347213 on Jan 19, 2016 18:55:28 GMT -5
Looks like oolitic jasper from NW Georgia. but it does not have 3.0 sg i will do a few more sg tests to see what kind of range i get
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br347213
starting to spend too much on rocks
Henderson, NV
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Post by br347213 on Jan 19, 2016 18:56:57 GMT -5
Whatever it is-fill your buckets up and take it home! Awesome colors! i went back and got most of it ?
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br347213
starting to spend too much on rocks
Henderson, NV
Member since October 2015
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Post by br347213 on Jan 19, 2016 19:01:41 GMT -5
so just a few more bits of info.
some of it does have banding, it's really nice too, the different layers are different shades of this same green.
it grows alongside gypsum. in fact some of it has fused with the gypsum. i found a small deposit of it one other location besides the original and it was the same deal.
other material in the are is 'dyed' this color. i found sandstone, gypsum, and various other common stones with a similar green tinge to it.
still scratching my head on this mystery!
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jamesp
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Post by jamesp on Jan 19, 2016 19:48:07 GMT -5
it sure looks like a jasper in Georgia formed from small marine life from the ordovician age. It can break into pieces of glass like fragments or be rather solid. The white and beige outer layer is hard limestone, calcium carbonate silicate mix. Is there a lot of limestone in the area ? perhaps fossils ? Dolomite occurs with it. I have seen it green. Here is a flickr set of other colors it comes in. In the adjacent county it is mostly green. Photos not representative, but when looking at it in it's natural state it looks very similar www.flickr.com/photos/67205364@N06/sets/72157635350617772
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br347213
starting to spend too much on rocks
Henderson, NV
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Post by br347213 on Jan 19, 2016 20:27:25 GMT -5
jamesp I can see the similarity. Is it harder than 7? Limestone, yes. Fossils, yes. Dolomite, yes. All the boxes are being checked. interesting....
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br347213
starting to spend too much on rocks
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Post by br347213 on Jan 19, 2016 20:32:52 GMT -5
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jamesp
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Post by jamesp on Jan 19, 2016 20:47:02 GMT -5
jamesp I can see the similarity. Is it harder than 7? Limestone, yes. Fossils, yes. Dolomite, yes. All the boxes are being checked. interesting.... Scratch test can be tricky. Some Mohs 7 rocks can be tough and hard, some brittle and hard. And hardness can be variable even in direction on the same rock. The sandy clay in your photos looks just like the clay the Georgia jasper occurs in. More so the way it fractures and the texture. If the fossils are Ordovician types as occur in many places in the US then that may be a hint. If no tectonic activity occurred then maybe the altitude would be similar to other occurrences of Ordovician marine fossils and jasper. I find ordovician materials around 800-1200.
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br347213
starting to spend too much on rocks
Henderson, NV
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Post by br347213 on Jan 24, 2016 19:59:34 GMT -5
Thanks for the info! I have a full batch in the 3lb rotary going now. Hopefully they're winners.
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Deleted
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Post by Deleted on Jan 25, 2016 23:44:08 GMT -5
My synopsis is based on your specific gravity. How reliable is it? Cannot be a carbonate for multiple reasons. Marble/dolomite out. Cannot be Jasper. Break is wrong and hardness and sg wrong. SG points to amphibole family. Cannot be jade, breaks too easy. Chemically similar go jade. Different enough to be harder but crystal form is wrong so not tough. Maybe pyroxene family? What is SG for pyroxenes? Gonna make a guess that it won't tumble well. Hard and brittle is not a recipe for tumbles. What is SG for bertrandite? There is beryllium in southern Nevada. Hardness correct, color not. How about SG? Sabre52 can you add anything?
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br347213
starting to spend too much on rocks
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Post by br347213 on Jan 26, 2016 21:34:13 GMT -5
My synopsis is based on your specific gravity. How reliable is it? Cannot be a carbonate for multiple reasons. Marble/dolomite out. Cannot be Jasper. Break is wrong and hardness and sg wrong. SG points to amphibole family. Cannot be jade, breaks too easy. Chemically similar go jade. Different enough to be harder but crystal form is wrong so not tough. Maybe pyroxene family? What is SG for pyroxenes? Gonna make a guess that it won't tumble well. Hard and brittle is not a recipe for tumbles. What is SG for bertrandite? There is beryllium in southern Nevada. Hardness correct, color not. How about SG? Sabre52 can you add anything? Thanks for the lengthy input. We'll see how they tumble when I take them out this friday. I'll be sure to report back and try to have an image for you. hopefully they aren't in a million little pieces. It kind of sounds like that though. So I finally had a chance to do more sg tests. 2.25 2.40 2.50 2.57 3.00 Average of all my test including the initial one is 2.62.
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Post by washingtonrocks on Jan 26, 2016 21:52:06 GMT -5
All of your data points to chert. Streak, fracture, and your new SG result. You mentioned gypsum which is helpful. Both gypsum and chert are sedimentary in origin and the fact that you're finding them both together, at least in my mind, sort of supports the chert idea. I have some green chert similar to yours with yellows and oranges that are really striking and take a great polish.
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Deleted
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Post by Deleted on Jan 26, 2016 21:58:46 GMT -5
All of your data points to chert. Streak, fracture, and your new SG result. You mentioned gypsum which is helpful. Both gypsum and chert are sedimentary in origin and the fact that you're finding them both together, at least in my mind, sort of supports the chert idea. I have some green chert similar to yours with yellows and oranges that are really striking and take a great polish. Nice. Would you say the fracture is chertlike?
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Post by washingtonrocks on Jan 26, 2016 22:16:17 GMT -5
I'd say so. The stuff I find has a microfibrous texture on the breaks. Almost velvety to the touch. And the breaks are conchoidal, but somewhat hackly too. Very similar looking to his. Maybe subconchoidal would be a better description for it. The fact that it shatters has me scratching my head a little though. But I've never dropped my precious finds to know one way or the other haha.
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Deleted
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Post by Deleted on Jan 27, 2016 0:16:50 GMT -5
I'd say so. The stuff I find has a microfibrous texture on the breaks. Almost velvety to the touch. And the breaks are conchoidal, but somewhat hackly too. Very similar looking to his. Maybe subconchoidal would be a better description for it. The fact that it shatters has me scratching my head a little though. But I've never dropped my precious finds to know one way or the other haha. I love a good mystery. Nice work everyone. OP, what is the precision of your scale used for SG?
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br347213
starting to spend too much on rocks
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Post by br347213 on Jan 27, 2016 21:17:36 GMT -5
wow interesting. i supposed chert comes in many variations but i've never seen it in this form. thanks for sharing your knowledge.
my scale precision is probably the issue as it's quite cheap and can only give me ounces or grams to the 1/10th decimal.
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Deleted
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Post by Deleted on Jan 27, 2016 21:49:42 GMT -5
wow interesting. i supposed chert comes in many variations but i've never seen it in this form. thanks for sharing your knowledge. my scale precision is probably the issue as it's quite cheap and can only give me ounces or grams to the 1/10th decimal. 0.1 grams is fine, if you use larger pieces. Since we are reporting to three significant digits our samples should have four or more. So 150-200 gram hunks would work.
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Mark K
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Post by Mark K on Jan 27, 2016 22:00:56 GMT -5
I was going to suggest that you send a sample to the rock professor, but it appears that he just died. (assuming it is the right dude)(I really hope I am mistaken)
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Henry
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Post by Henry on Feb 18, 2016 14:29:22 GMT -5
Flint? Chert? But I think the aforementioned is harder than 6.0. <scratches head>
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RocknCritter
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Post by RocknCritter on Feb 18, 2016 16:12:33 GMT -5
Any chance it's Jade? I've heard that can be found in Nevada, but not sure about that far south. FYI: The guy selling Nevada "jade" at the rock shows in the western U.S. high graded his friends claim after his buddy took him out there as a favor. A real scum bag in my opinion.
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