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Post by tntmom on Oct 16, 2011 17:34:11 GMT -5
Please help me ID this! This rock is waxy like Jade but is yellow/brown. It's transparent. I do not want to cut into it until I know what it is.... Back-lit to show transparency: Thanks for helping me out!!
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unclestu
Cave Dweller
WINNER OF THE FIRST RTH KILLER CAB CONTEST UNCLESTU'S AGUA NUEVA AGATE
Member since April 2011
Posts: 2,298
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Post by unclestu on Oct 16, 2011 17:39:25 GMT -5
Could it be yellow calcite? Stu
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Post by kk on Oct 16, 2011 18:00:32 GMT -5
Can't name it, but looks like matrix from Turkish Dendrite Opal.
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Post by jakesrocks on Oct 16, 2011 18:08:17 GMT -5
If it's waxy, I'd say common opal. From the looks of all the fractures, you probably won't get much usable material out of it.
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nuevomundo
starting to spend too much on rocks
Member since March 2010
Posts: 222
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Post by nuevomundo on Oct 16, 2011 19:05:39 GMT -5
if it is softer than opal (~3 mohs hardness), then serpentine would be a possibility. if it is harder (~5.5 or so) then common opal seems a good guess, as others have suggested.
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Post by tntmom on Oct 16, 2011 19:11:52 GMT -5
Penny doesn't scratch it.... but it leaves copper on the rock?
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Post by tandl on Oct 16, 2011 20:38:39 GMT -5
i agree ,on opal
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nuevomundo
starting to spend too much on rocks
Member since March 2010
Posts: 222
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Post by nuevomundo on Oct 16, 2011 21:04:38 GMT -5
Copper is about 3, think, and serpentines can vary from 2.5 to 4. I'd try scratching it with a steel blade or pin. If it is serpentine it should scratch without much trouble. If a steel pin doesn't scratch it, then I would go with opal...
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Post by jakesrocks on Oct 16, 2011 21:11:33 GMT -5
Fresh fracture in pic 1 doesn't look like serpentine.
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Post by tntmom on Oct 16, 2011 21:18:08 GMT -5
Hmmmm... A thumbtack scratches it. Below you can see the smiley face I drew with the thumbtack and the other two scratches I did just to the left of it.
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Post by tntmom on Oct 16, 2011 21:27:29 GMT -5
Here's a picture of the other side of the rock if it helps.
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Post by jakesrocks on Oct 16, 2011 21:28:02 GMT -5
Krystee, just out of curiosity why don't you put a match to a little chip, and let us know if there's an odor of burning pine ? I'm probably way off base, but just want to make sure you don't have a very large piece of amber.
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Post by tntmom on Oct 16, 2011 21:48:57 GMT -5
That didn't work either. No pine smell, just a "hot" smell, Didn't discolor the stone any either...
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Post by jakesrocks on Oct 16, 2011 21:58:49 GMT -5
Hmmmmm. I'm still going with opal.
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nuevomundo
starting to spend too much on rocks
Member since March 2010
Posts: 222
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Post by nuevomundo on Oct 16, 2011 22:15:37 GMT -5
I would go with serpentine. An opal should be too hard to scratch that easily.
I have imported serpentine rough from Peru that has a similar color and translucency. If you grind it and it spits off whitish, foamy mud, then you can be 100% certain it is serpentine.
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rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
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Post by rockhound97058 on Oct 16, 2011 23:11:50 GMT -5
I support the common opal - Where I live in Oregon I have seen thousands of pounds of material like this. What gives it away for me is the fractures, the way it breaks apart and it just has the look I'm used to. Much of the material we have around here is either associated with Petrified wood as either a bog wood, or just left over material that forms around larger tree's and roots.
Also Krystee - I need to take a picture and show you - Since you love your obsidian, I finished a Obsidian sphere today. Unsure what type as it's a strange colored, banded obsidian. It's not a sheen variety, just a odd piece I got in a collection.
Jason
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Oct 18, 2011 15:38:49 GMT -5
New here but thought I would throw in my one cent worth. I have a bunch of calcite here in north central Wyoming that looks exactly the same. I scratched it with a thumb tack and got the exact same scratch that you got (well, not the smiley face). If you could come up with a little acid you could drop a little piece in and know for sure. It will bubble and disappear quickly. Hope this helps. Jim
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Post by jakesrocks on Oct 18, 2011 15:59:16 GMT -5
Jim, the acid test is easy and safe enough, if it's calcite. Just crush a little chip with a hammer. Lay the powder on a glass dish and put a drop or two of regular household vinegar on it. The vinegar is a strong enough acid to make is bubble. You may need some sort of magnification to see the bubbles.
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Post by susand24224 on Oct 19, 2011 0:31:36 GMT -5
Krystee--are there little bits of white powder in the crevices? It sure looks like some of the common opal from central Washington. At the Spokane Rock show during the summer a few vendors were selling it by the name of "honey opal." Even the fractures are similar to what the local common opal does if it freezes.
The opal here shouldn't scratch with a thumb tack, but the surface will deteriorate a bit with exposure (sometimes) and that might make it more scratchable.
Ron is right--the quantity of fractures is not promising for future cutting, and, if common opal, is likely a head's up that the rock isn't stable.
Susan
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Post by mohs on Oct 19, 2011 0:41:04 GMT -5
excellent! ;D
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