Crystilne gold?

[SammyJ]

Can crystilne gold on quartz be so thin it looks like gold leaf?

 

[silver]

You'd need to use a microscopic to tell Sam.

 

[user 1769]

Can crystilne gold on quartz be so thin it looks like gold leaf?

Yes, definitely.

 

[SammyJ]

Can crystilne gold on quartz be so thin it looks like gold leaf?

Yes, definitely.

Thanks mfdes, I'm thinking its Pyrite but it is so yellow. I have a lot of quartz rocks from the vic triangle im studying and this one is different from the normal pyrite. It's almost like a golden spray paint.

I'm having a look at your blog by the way. Great work!

 

[user 4386]

Yes, defintiely. During the gold rushes they would call it "New Chum gold" (they also called pyrite that in some areas). With pyrite it was because the New Chum on the goldfields would mistake it for gold. However with the gold film, it was because it made a great display on quartz outcrops, but when mined it rapidly disappeared to become low-grade primary gold at depth. It is almost certainly supergene gold that has dissolved and then been re-precipitated as a thin film - you can tell with an SEM - in Victoria the original gold contains 50% silver (eg St Arnaud, around Omeo etc), more typically 5% or a bit less silver dissolved in the gold. With supergene gold it is commonly 99.7% gold and the remainder is usually copper or iron, not silver. The weathering and re-deposition process only re-deposits gold, the silver stays in the groundwater and moves elsewhere (the St Arnaud mines started as silver mines for that reason - the silver would deposit separately in fractures, running kilograms per ton near surface - at depth it dropped off to equal or slightly more than the gold content of the ore. Where you get it, the supergene gold also occurs in other forms, some replacing the shape of bacteria, other colloform - here is one of our photos of the latter.

 

[Ramjet]

Crystalline gold is such a beautiful thing... not that any gold isn't gorgeous.
Some topics on crystalline gold.....

https://www.prospectingaustralia.com/forum/viewtopic.php?id=10087

https://www.prospectingaustralia.com/forum/viewtopic.php?id=7304

https://www.prospectingaustralia.com/forum/viewtopic.php?id=5175