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Post by scienceteacher79 on Nov 10, 2020 0:40:50 GMT -5
I find these nice green rocks from time to time along the Snake River in Idaho. Any help in identification would be appreciated. They seem to be a hardness of 4.5-6 as it is hard to get a nice shine on them in the tumbler. It is a matte rather than gloss finish. I was told by a local that it might be serpentine, but I don't think that is right. It reminds me of ricolite, but that is supposed to be limited to a small area of New Mexico.   
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Nov 10, 2020 3:47:51 GMT -5
I find these nice green rocks from time to time along the Snake River in Idaho. Any help in identification would be appreciated. They seem to be a hardness of 4.5-6 as it is hard to get a nice shine on them in the tumbler. It is a matte rather than gloss finish. I was told by a local that it might be serpentine, but I don't think that is right. It reminds me of ricolite, but that is supposed to be limited to a small area of New Mexico. Some of those photos do indeed look like ricolite. If they were found along the river where it forms the border with Oregon, that contains parts of the Baker Terrane and Wallowa Terrane formations. Possibilities include greenschist and possibly some mylonite granite (in the case of the 2nd-to-last one). There are some copper-bearing and epidote-bearing deposits along that stretch, as well. |
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Post by Peruano on Nov 10, 2020 7:32:34 GMT -5
I sympathize with you. Green rocks can be tough to identify. They have a ricolite pattern but to my eye they are not "soft" enough to be that. There is a whole family of metamorphics called green stone that apparently blend through a wide array of minerals together with olivines. I have a lot of similar material from a beach in Guaymas Mexico and likewise lack a trustworthy id. Welcome.
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Post by orrum on Nov 10, 2020 10:53:51 GMT -5
Purty they are in their matte finish.
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Post by 1dave on Nov 10, 2020 11:28:59 GMT -5
I find these nice green rocks from time to time along the Snake River in Idaho. Any help in identification would be appreciated. They seem to be a hardness of 4.5-6 as it is hard to get a nice shine on them in the tumbler. It is a matte rather than gloss finish. I was told by a local that it might be serpentine, but I don't think that is right. It reminds me of ricolite, but that is supposed to be limited to a small area of New Mexico. Some of those photos do indeed look like ricolite. If they were found along the river where it forms the border with Oregon, that contains parts of the Baker Terrane and Wallowa Terrane formations. Possibilities include greenschist and possibly some mylonite granite (in the case of the 2nd-to-last one). There are some copper-bearing and epidote-bearing deposits along that stretch, as well. I agree. They appear to be metamorphic sediments. |
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gemfeller
Cave Dweller 
Member since June 2011
Posts: 4,047 
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Post by gemfeller on Nov 10, 2020 16:20:42 GMT -5
@scieneteacher79, what part of the Snake are you collecting on?
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Post by fernwood on Nov 10, 2020 22:58:27 GMT -5
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Post by rmf on Nov 11, 2020 6:25:06 GMT -5
scienceteacher79 Ricolite is a variety of serpentine. ( Ricolite is a variety of a Serpentine species interbanded with Talc. The material to the best of my knowledge only comes from the Ash Creek tributary of the Gila River in Grant County, New Mexico. The name "Ricolite" is from the Spanish "rico" for rich, i.e., "rich stone".) Based on your images Serpentine is a good/correct diagnosis.
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Post by scienceteacher79 on Nov 12, 2020 11:55:11 GMT -5
What do you think of epidote as a key mineral in some of them?
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Post by scienceteacher79 on Nov 12, 2020 11:56:10 GMT -5
@scieneteacher79, what part of the Snake are you collecting on? I am collecting in Gooding and Twin Falls Counties in S. Idaho. |
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pizzano
Cave Dweller
Member since February 2018
Posts: 1,390
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Post by pizzano on Nov 12, 2020 12:29:26 GMT -5
@scieneteacher79, what part of the Snake are you collecting on? I am collecting in Gooding and Twin Falls Counties in S. Idaho. Common Geological formations in those areas......:
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Tommy
Administrator 
Member since January 2013
Posts: 12,956
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Post by Tommy on Nov 12, 2020 15:19:05 GMT -5
catmandewe, Tony (Idaho Rock Shop) is from Gooding - maybe he knows something about it
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