Cubic stones found while panning for gold

[Ivan]

Hi everyone,

I need help to identify stone/rocks...
When panning for gold I have found three little cubic stones. Smallest ~2.5mm each size, medium ~3mm biggest ~3.5mm. One of them good magnetic, one no magnetic and one is just enough to stick to rare earth magnet.
I have never seen anything like this before and quite curious what it is.

Thanks in advance
Ivan

 

[RedDirtDigger]

Hi Ivan you have some Devils Dice. They are made of the mineral Limonite or similar minerals. They derive from Iron pyrite crystals where the pyrite weathers and becomes limonite. (iron mineral)

Plenty on them if you google and also on this forum a few times including. https://www.prospectingaustralia.com/forum/viewtopic.php?id=2601

They are relatively common and in some places the ground can be covered in them.
I found one years ago with a detector that had a coating of gold on two faces. It was among 10s of thousands of them on a mullock heap in Temora nsw
cheers RDD

 

[Tathradj]

Also got one at Tuena.
Only thing heavy in the pan but I laughed when
I had a closer look. Fools Gold.
Put it in acid and it was half Real Gold as well.

 

[Ivan]

Thanks RedDirtDigger and Tathradj!
Google says also they are a real good gold indicator, so just need to continue digging
To dissolve them any specific acid or just sulfuric acid is good enough?

 

[jethro]

Yeap RDD nailed it, Devils dice they are If you are getting them in the pan you are digging in the right place. As for disolving them in acid Normal HCL or brickies acid from bunnings is the best just dilute it about 50 percent water But remember the old chemist rhyme.''Do like you oughta add the acid to the water.'' Not the water to the acid or you may get an exothermic reaction. Oh and wear gloves and glasses etc.

 

[Ivan]

Thanks all for information and precautions.
Was able to dissolve one of them and nothing in it.
Took a coupe photos to share with other novice if any curious