Discussions

╳Discussions

Groups

Recent Images in Discussions

Improving Mindat.orgBeithauptite & Silver

25th May 2012 23:52 UTCReiner Mielke Expert

http://www.mindat.org/photo-466720.html I see no silver in this photo, however I see lots of Ni-Co arsenides on the breithauptite.

26th May 2012 18:39 UTCRob Woodside 🌟 Manager

message sent

26th May 2012 22:01 UTCKelly Nash 🌟 Expert

I'll try to post some better pictures later. The dark layer that is on the inside of the void is what I believe to be silver. Contiguous with that layer on one side of the specimen is a hackly mass with some "ropiness" that looks like silver to me, and also a few very small lustrous silver-colored cubes (~0.1 mm.) that look like silver crystals. So far I haven't been able to get decent photos of those.

I only have the label to go on, but comparing the specimens to similar ones here and elsewhere on the internet, it seemed like a credible ID. That said, I don't know the associations here that well, so I would certainly consider other possibilities. Curious about the visual ID of arsenides.

27th May 2012 00:43 UTCReiner Mielke Expert

The cubes would be skutterudite, silver crystals are never found in that association and never in cubes. Also if it is silver it should be malleable, test it with a needle under the scope.

27th May 2012 17:13 UTCKelly Nash 🌟 Expert

You are right, Reiner. The gray mineral is brittle, not malleable. I'll remove the silver ID in a minute. Here is a photo of the part that had me agreeing with the label, a 6 mm. hackly mass that sticks out to the side and that is perhaps a pseudomorph of arsenides after silver(?). Also can kind of see on the lower left, reflections off the cubic crystals I referred to. I had thought they were awfully bright for silver xls, but had not considered skutterudite, which makes more sense. Thanks for the catch!

http://www.mindat.org/forum.php?file,7,file=38639,filename=Breithauptite_Cobalt_ONTsml.jpg

28th May 2012 01:49 UTCReiner Mielke Expert

Hello Kelly,

That sponge like mass sure looks like silver. If it is brittle then it may be allargentum, which is not uncommon in that area. If you dissolve a small piece in a drop of nitric acid under the scope and then add a tiny grain of salt after it dissolves,you will get a white precipitate if it contains silver.