FMF - Friends of Minerals Forum, discussion and message board

[Albert Chan]

I recently acquired two gold specimens for my collection. They came from California and were found about 30 years ago on a steep hillside of decomposed quartz. I have attached a few pictures of the larger of the two specimens. It weighs 29 grams. From the pictures it looks as if it is a pseudomorph of a mineral like Pyrite as virtually all the surfaces have striations on them. I have not seen any gold with such formations before and would like to know whether any one has come across anything similar (gold or other minerals). Also, I would like to know whether anyone knows whether it is a psedomorph or epimorph. Thanks.

[Maxilos]

Welcome to FMF Albert,

I only can help you to fine out if it is gold. Hold the specimen in the sun. If correct it glisters. Than, hold your other hand above the specimen to block it for the sun. If it's still glistering, it is gold.

Regard,

Mark

[Albert Chan]

Thanks, Mark. It IS gold indeed ! I have also carried out a specific gravity measurement on the specimen and it is 18.0 (pure gold has a specific gravity of 19.3).

By the way, only two of such specimens were found in this locality and I bought both of them. The prospector kept them for 30 years before deciding to part with them.

[Maxilos]

Wow,

That means you got almost pure gold! I have never bin to America before, possebly becaue of my age (15), but if I ever go, I'll make sure I find someone who sells similar ones to youres. I see the pictures and it lis a magnificent specimen and if I think about the fact that you got two of these specimens, than you must be very lucky!

Mark

[Peter Megaw]

Gorgeous pieces Albert, Congrats!

Below are copies of 2 of the 8 pages of crystal drawings of gold from Goldschmidt's classic Atlas der Krystalformen...these show plenty of examples of gold crystals with striations that intersect at angles similar to those on your specimen.

We would love to see this piece exhibited at Tucson some year!

[Albert Chan]

Thanks, Peter, for the sketches.

I do not recall that any of my crystallized gold specimens ever has striations that cover the full crystal faces. If striations do occur, they only occur on a small portion of the faces.

It didn't really occur to me till now that the specimen could be a conglomeration of some gold crystals (with striations on their faces) arranged into a complex helictite-like formation. If this is really the case then they are indeed very rare and unusual.

Thank you very much for highlighting this possibility to me !!! It is most enlightening - I really appreciate it.

I have never been to the Tucson Show and would like to go there one day.

[Peter Megaw]

Another possibility to consider is that some of these may be molded impressions of striations on crystals that originally were intergrown with the gold but are now gone.

[Albert Chan]

Yes, the possibility is there (ie it is an epimorph). But I understand that only quartz is found there and I do not think that quartz crystals have such consistent striations on their faces.
Unless it is another mineral like pyrite that has since 'dissolved' away without leaving any traces over the millions of years.

[lluis]

Good evening, Albert, Peter

Well, I was thinking same possibilites as Peter.
First that maybe are twinned cristals showing this striations, but then thinking that is more likely as a filling in cavities among quartz crystals.
I think to remember that was a find of bismuth that had same aspect of your gold, except that it was grey, of course...
I think to remember that was from Australia also.
And yes, were form there
If you would like to take a look at the pieces under Wolfram Camp locality
https://www.mindat.org/loc-146.html
you could get an idea.

With best wishes

Lluís

[Albert Chan]

Thanks, Lluís, for your input.

Regards.

Albert