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What is the dark green gemmy material in the center of the specimen?

Posted by Anonymous User  
Anonymous User July 03, 2012 01:36AM
I found what I think is a Serpentine specimen a couple years ago - gemmy side down in the Rock River, downstream from the Adams Hill Nickel prospect, in southeastern Vermont. It happened to be a sunny day and I knew I had something of some significance, at least to me. So I decided to polish it with my orbital sander, working my way up with finer grits and then some automotive chrome polish. I know there is asbestos present in serpentine, so I took proper safety precautions. My question is: what is the gem-like material in the center of the specimen - when tilted, different structures (or bands) are highlighted depending on the angle of tilt - a "holographic" effect is produced. Thanks for your help:-D

Edited 1 time(s). Last edit at 07/03/2012 01:39AM by Timothy Bonura.
open | download - P1030018 - 2.jpg (30.8 KB)
D Mike Reinke July 03, 2012 05:05AM
Can we get a larger picture, and maybe several angles? I think that would generate more responses.
Anonymous User July 03, 2012 10:14PM
Here are some better photos - I hope these are helpful. Thanks!
open | download - P1020834 - 2.jpg (182.1 KB)
open | download - P1020835 - 2.jpg (209 KB)
open | download - P1030018 - 3.jpg (380.4 KB)
Paul Brandes July 04, 2012 12:07AM
Have you conducted any sort of diagnostic testing yet such as hardness, streak, specific gravity, etc...? That might also give you (and us) a better idea of what you have. My initial thought is that if you used an orbital grinder to polish it, it is likely harder than just serpentine alone but is a metamorphic rock called serpentinite, which contains serpentine minerals.
Anonymous User July 06, 2012 01:21AM
Dear All, After further research I've narrowed it down to Bowenite a variety of Antigorite. Thank you again. Timothy Bonura
Peter Haas July 06, 2012 11:56AM
Please be aware that the various serpentine group minerals cannot be distinguished by visual means. There may be good reasons to assume that it is bowenite (you probably checked what has been published about the locality where it was found), but until it is confirmed by an appropriate analysis, it remains an assumption.
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