spiceman848
off to a rocking start
Member since April 2016
Posts: 16 
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Post by spiceman848 on Nov 25, 2016 21:25:49 GMT -5
I got a collection of rocks with no information at all, just in boxes. Attached are photos of a rock I might have a guess but I won't say. I think maybe from Michigan but only a guess. I appreciate all the info I can't get. Only MOHs test... A file skips right off. Late me know if other testing will help? Dale  TOP SIDE  TOP SIDE-closer  RIGHT SIDE, WHITE SPICKS OF CRYSTALS  THE LAYER WITH CRYSTALS GOES ALL THE WAY TO THE OTHER SIDE.  END VIEW |
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ziggy
spending too much on rocks
Member since June 2016
Posts: 483 
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Post by ziggy on Nov 25, 2016 21:54:25 GMT -5
Maybe alabaster??  |
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Post by spiceman on Nov 25, 2016 22:13:22 GMT -5
I will check that out.
Thanks
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Post by vegasjames on Nov 25, 2016 22:29:30 GMT -5
Alabaster is gypsum and would be very soft.
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Post by vegasjames on Nov 25, 2016 22:31:19 GMT -5
The upper photo looks like a chalcedony. The last photo looks like a quartz.
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Post by spiceman on Nov 25, 2016 22:37:36 GMT -5
All the pics are of the same rock.
Chalcedony, the edges are sharp and the surface is smooth(just like flint)
But the crystals, I don't know.
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Post by spiceman on Nov 25, 2016 22:49:03 GMT -5
The crystals...
Well, it is in the quartz class.
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ziggy
spending too much on rocks
Member since June 2016
Posts: 483
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Post by ziggy on Nov 26, 2016 8:34:48 GMT -5
Alabaster is gypsum and would be very soft. Yeah, I didn't do a scientific study on what it might be. Just searched for michigan rocks since he said he thought it was from michigan. Found one that looks like his. Like I said, nothing to stringent was used in my idea. The rock in my photo is Alabaster and not quartz. Even the Alabaster I was referring to was not the Gypsum variety. This following passage was from the wiki on Alabaster: "Alabaster is a name used in two different fields with two different meanings. This article concentrates on the archaeological and stone trade professional meaning of the word. They define "alabaster" by a set of external characteristics: a usually light-coloured, translucent and soft stone that has been used throughout human history mainly for carving decorative artifacts. In this sense it refers to both gypsum and calcite, two distinct varieties of minerals.[1] Geologists define alabaster strictly as a compact and fine-grained variety of gypsum.[2] Chemically, gypsum is a hydrous sulfate of calcium, while calcite is a carbonate of calcium.[1] The calcite variety is also known as onyx-marble, Egyptian alabaster, or Oriental alabaster and is geologically described as either a compact banded travertine[2] or "a stalagmitic limestone marked with patterns of swirling bands of cream and brown".[1] "Onyx-marble" must be understood as a traditional, but geologically inaccurate term, since both onyx and marble have geological definitions distinct from even the widest one applicable for alabaster." I was referring to the calcite variety, My apologies on how sloppy I was. I should have just called it calcite. As always, the best way to get help identifying a rock or mineral is to not only post a photo, but do some preliminary testing of your own before asking for help. Do a scratch test. (Now I see you said a file skipped off so it must be hard as he**. I missed that part when I first read your post. Was that edited in later?) Did you actually try and just drag the corner of the file across it to scratch it? Do a streak test. Drop some acid on it. See how it fractures. If possible, do a specific gravity test. If you can't narrow it down some that way, there is no way someone can actually tell what someone else has just by a photo. |
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Post by spiceman on Nov 26, 2016 22:26:43 GMT -5
Thank you ziggy
As far as the scratch test,I tried the file on a sharp edge. No, it was not edited afterwards. The scratch test was do over dark paper so I could see if material was being removed. I will redo that along with the other tests.
I will post the test results you mentioned, the specific gravity my be hard because I need to find a scale.
But, not very good on the right testing to do. But now I have a list of tests to complete.
Thanks again.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Nov 27, 2016 12:36:28 GMT -5
If a file doesn't scratch it, acid test unnecessary.
Many times agate grades into quartz, think Brazil agates.
This does seen to be agate by texture and the druzy tells us a lot.
I'd be happy with agate family stuff...
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ziggy
spending too much on rocks
Member since June 2016
Posts: 483
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Post by ziggy on Nov 27, 2016 13:31:36 GMT -5
If a file doesn't scratch it, acid test unnecessary. Many times agate grades into quartz, think Brazil agates. This does seen to be agate by texture and the druzy tells us a lot. I'd be happy with agate family stuff... I was just suggesting some things he could test before asking. Not necessarily in any order. Let common sense rule of course when doing tests. |
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Post by spiceman on Nov 27, 2016 21:32:29 GMT -5
Common sense? Me? Don't put pressure on me.:)
For rock testing, Im very new to rocks.
I can preform most all testing(maybe) but not sure what it means. Sometimes.
Thanks
Dale
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Post by Peruano on Nov 28, 2016 7:18:10 GMT -5
I'm going to go with quartzite. Fine but distinct crystals, can fracture with flat surfaces like that. Its most likely in my opinion.
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Post by spiceman on Nov 28, 2016 21:32:43 GMT -5
Thank you
But what's that mean? I know Quartz but this is a solid bunch of colors.
I need to research that better.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Don't know
Nov 28, 2016 23:19:36 GMT -5
via mobile
Post by Deleted on Nov 28, 2016 23:19:36 GMT -5
Quartzite is quartz sand metamorphosed into a solid material. It generally has a grainy texture and look to it. Takes a nice polish usually.
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