Evening GeoFiji ........... Throwing those to me on a Easter Sat...

Evening GeoFiji ........... Throwing those to me on a Easter Sat at 10pm is like receiving a backhand serve at 200kph + and, in the dark ! LOL

Your Q's .......

1. Is the bright blue actually Chrysocolla? Probably not.
2. If so can the darker purple mineral be Chalcocite or Cuprite? High probability of yes to Chalcocite.

To determine the exact composition from the picture of that had specimen is extremely difficult ; the vagaries of supergene enrichment, so complex.

Lets look at the pic of that specimen and perhaps suggest a couple of options and why.



1. Pointing to a deep and enriched green, possibly Chrysocolla, somewhat veined.
2. Looking at a very rich blue, does it have the texture of Chrysocolla? Possibly not. Potentially Auzurite.
3. The round texture on this point could possibly fit the texture of Chrysocolla, botryoidal ? It does appear some what round, and of the greenish colour. But, Malachite can also áppear'as botryoidal as well, I'm sure we have all seen radiating textures of Malachite in hand specimen.

But again, the vagaries if identifying supergene enriched minerals in hand specimen is difficult. A nice little PS/TS using an electron probe microscope scanning across the surface would tell us a huge amount. Even with little or no intergranular relief between the minerals, there is still the possibility of the chemistry on the Cu minerals merging into one another. That may make our determination inconclusive.

Back to Q1, Chrysocolla, a couple of micro images and my very old explanation of the possibilty of this, still difficult at time. A view of a TS/PS of such a micro view below.
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My description below. Note the vein effect of Chrysocolla in ordinary transmitted light in the top micro pic. Typical from my observations around the lower part of the Gawler Craton is South Aust. Note, which may be Chrysocolla.

So can we conclude that the possibility of Chysocolla in that hand specimen may only be minor at the very best.

If it were Chrysocolla, lets not get too excited, as the best metallurgical Cu recoveries of the mineral I have heard of is generally around 10% for the minor supergene enriched mineral.

Q2. Is ...... darker purple mineral be Chalcocite or Cuprite?

As much as I would like to see it being Cuprite ~ 88% Cu, I am still very happy with it being Chalcocite at ~ 79% Cu, and knowing that this specimen was collected from a shallow depth, the probability of it being Chalcocite is high.

But who knows?

Who would ever expect to find Chacocite at + - 300m in depth? It happened in the discovery hole RD1 at Olympic Dam/Roxby Downs.

Have a read of the clip I will insert from David Upton's book below. A book that all geos should read !

Page 109, a must buy ! It was the suggestion by Douglas Haynes to target SA in the early days for a Cu discovery by WMC, he was spot on.

So getting back to our project, the sky is the limit for some spectacular intersections in and around the workings of this project. Why it has been left for so long and untouched probably amazes most of us. The potential for these random workings looks very promising in finding some great associations and or extensions at depth.

And of course let us not forget the potential Au credits !

Could it be that these supergene enrichments may be similar to the lower Gawler Craton examples that I have seen, and with another credit of Covellite ! Could it happen, see one of my older reports and a photomicrograph of just one example and its description below. Gold.


So that little description above, do we see this happening at LF or ND, time will tell very soon !

Again GeoFiji, we could reflect on some of the historical reports that you have revealed, and obviously Cuprite is not out of the question.

In concluding, thanks GeoFiji, but there is no need for bowing to anything that I write as superior knowledge, as we are all up in the air as much as one another at this point in time. I am just a very old Archean rock head. LOL

I feel that we are hovering around some very significant revelations on this project.

GLTAH ...... my apologies for such a boring post.