Draino
off to a rocking start
Canadian Rocker
Member since July 2006
Posts: 15
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Post by Draino on Aug 27, 2006 13:12:27 GMT -5
I found this yesterday in a river bed close Grande Prairie Alberta. I am not really sure what type of mineral this is. It envelopes the whole rock everywhere and has this globular texture , and is yellow to dark yellow in color
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,456
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Post by Sabre52 on Aug 27, 2006 13:48:17 GMT -5
Hmm. Kinda depends on hardness, My guess would be travertine ( calcite onyx) if it's soft as it is often laid down as coating around other materials. Chalcedony is often botryoidal and has that formation type too. The travertine will easily scratch with a knife while the chalcedony ( agate) is hard and will not.....mel
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Draino
off to a rocking start
Canadian Rocker
Member since July 2006
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Post by Draino on Aug 27, 2006 13:56:45 GMT -5
I can scratch this with a knife, but not with a penny . Sounds like it could be travertine.... Thanks for your help
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Draino
off to a rocking start
Canadian Rocker
Member since July 2006
Posts: 15
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Post by Draino on Aug 27, 2006 14:44:23 GMT -5
I got one more that I need help with please, I found this in the same area . It is translucent orange in color , and it can not be scratched with a knife or a file edge. Any guesses what it might be?? TIA
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
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Post by Sabre52 on Aug 27, 2006 18:28:18 GMT -5
Now that one looks like an excellent nugget of carnelian. Real gemmy. Actually nice as it is but should tumble up excellent too....mel
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rollingstone
starting to spend too much on rocks
Member since July 2009
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Post by rollingstone on Aug 28, 2006 3:01:26 GMT -5
I'm with Mel, that does look like classic carnelian (and a particularly nice piece as well!) But in Alberta??? Hmm, I don't recall ever hearing of carnelian in the province before (I'm in Edmonton) -- For the time being, I'd hang on to that as a specimen, as you might have found something really special there!
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Post by hermatite on Aug 28, 2006 12:31:36 GMT -5
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Draino
off to a rocking start
Canadian Rocker
Member since July 2006
Posts: 15
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Post by Draino on Aug 31, 2006 22:29:41 GMT -5
Thanks for all the help. Is there a way to test if this is carnelian or an agate ??
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,456
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Post by Sabre52 on Sept 1, 2006 12:45:15 GMT -5
Draino: Carnelian is just more or less a color variety of translucent agate. Usually any transluscent agate in the orange to red range is carnelian. If more brown or yellow it's usually called "sard". Agate is just sort of a general catagory for microcrystalline transluscent quartz. If opaque, the microcrystalline quartz is usually called jasper, flint or chert depending on origin...mel
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rockcandy
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Member since June 2006
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Post by rockcandy on Oct 9, 2006 6:44:01 GMT -5
Hello, I have found quite a few rocks in the South Dakota Badlands that look identical to yours. The yellow, harder layer either envelops the dark grey rock, or runs in veins through it. I do not know what it is either, but the dark rock seemed to be sedimentary IMHO. In all the samples I have found the yellow layer is of the same thickness as in your photo.
I want to add- I also, for the first time in the Badlands, found a small piece of carnelian (just got back last week). Was surprised to find it there, though it is known to exist in that area. Interesting that you are finding similar, South Dakota badlands-type rocks in Alberta!
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