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Let's Rock => Identifications of Materials => Topic started by: Itsandbits on March 31, 2015, 03:41:45 PM

Title: hard green somewhat translucent
Post by: Itsandbits on March 31, 2015, 03:41:45 PM

I found this in the Fraser river a month ago and decided to cut a cab today to try it out; curious as to what you think it might be. It is hard; agate won't scratch it and it won't scratch agate but it will scratch the black jade; about mohs 7, which the agate won't. It is tough, has a fine grained brittle fracture, The speckles aren't sparkly, and it polishes like a dream, When backlit there is a yellowish tone to the translucence. I thought it might be another version of the sillimanite but ???? Things seem to point that way. It is heavy for it's size but I haven't done an sg yet
(https://lh4.googleusercontent.com/hJeNuqTfxSqbld0wLX3QjMIuFSlp2XcP4wWFlfdOuQS1=w1278-h647-no)

Title: Re: hard green somewhat translucent
Post by: Enchantra on March 31, 2015, 04:31:22 PM

Reminds me of massive forms of green garnet I've seen before that come out of Africa.  Hrm...
I would say Adventurine, but the hardness doesn't match, so that's out.

Title: Re: hard green somewhat translucent
Post by: Gergis on March 31, 2015, 05:56:14 PM

All the speckles reminds me of goldstone sort of :-)

Title: Re: hard green somewhat translucent
Post by: lithicbeads on March 31, 2015, 06:31:22 PM

 It looks like feldspar aggregations in a metaquartzite . Metaquartzites can be extremely hard. The feldspar can be from a metamorphic process that changes garnets to feldspar. There is much evidence in the literature for that process with our metaquartzites down here.