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Australian opal with dendrites

Posted: Wed Mar 20, 2024 7:17 am
by Craig
Hello all was cutting some opal again today and I cut this little guy. 1.7 carats and I believe it has dendrites in it and I've never seen it in Australian Opal. Or am I just sheltered? Lol
any feedback would be appreciated

Re: Australian opal with dendrites

Posted: Thu Mar 21, 2024 5:39 pm
by SwordfishMining
Hiya. Thats neat looking. I cant say I've run across a picture like that before. But manganese does like to make dendrites and i was lead to believe white opal was opaque because of manganese oxide or something like that with iron or manganese as what made black opal black too & I think it maybe also attributes the UV glow to that.
But we have a lot of sulfur here in volcano lands around the world making sulfides which are not the best in the stability mix. Somewhere I read desert varnish was a variety of air deposited black opal.
Thanks for sharing that one.

Re: Australian opal with dendrites

Posted: Tue Mar 26, 2024 8:53 am
by OpalSpectrum
Hi Craig , I think this is 'black potch webbing' which sometimes can form odd shapes inside the crystal opal > like in your example
*some Lightning Ridge opals have a lot of potch webbing very similar to Ethiopian opals - I might create post about it :roll:

here are some similar crystals which I've cut couple years ago ?





hope this helps
;)