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Unknowns from Cornwall

Posted by Alan Barnes (2)  
Unknowns from Cornwall
June 24, 2012 08:15PM
I have a large cabinet sized specimen of uraninite from St. Terras Mine in Cornwall. Sat on the quartz matrix are two blue, presumably copper, minerals. Do any of you Cornish experts know what these two minerals are? One is a pale blue whilst the other is a much darker blue. There are no crystals because I broke a huge specimen in two and the blue patches were found in between the tightly packed quartz crystals. The very small amount of these minerals on the specimen has prevented me from being able to do a streak test so unfortunately I can't offer anything scientific that might help people identify the minerals........but if anybody has any ideas I'd be glad to hear them

Best wishes,
open | download - cornish unknown 1.JPG (194.4 KB)
open | download - cornish unknown 2.JPG (132.5 KB)
avatar Re: Unknowns from Cornwall
June 24, 2012 08:28PM
Welcome to the world of the Blue/Green Grotties. Could be malachite, chrysocolla, connellite, botallacite, atacamite, paratacamite, brochantite or one of a dozen others. Unlikely to be able to identify it much further without some chemical work (eg dissolving in acid)
avatar Re: Unknowns from Cornwall
June 24, 2012 09:16PM
Maybe a uranium secondary, being with uraninite?

-Rowan Lytle

Food, Water, Shelter, Fire, Minerals.
avatar Re: Unknowns from Cornwall
July 01, 2012 07:32PM

Re: Unknowns from Cornwall
July 01, 2012 08:09PM
I love these green grotty things you never know what thy might be,
I would guess at something like Brochantite/Malachite on Native Copper for the 1st photo
The 2nd photo could be Malachite, it can be very pale green, or my be completely some thing else.


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