Is this pyrite?

G'day everyone.Im regularly over in Perth from Melbourne visiting family and while there recently in picked up this rock which was glistening in the sun on the banks of the swan river.Heavy for its size.
I have noticed boulders used to shore up the banks have heaps of pyrite which looks different to this rock,it's just a solid silver colour

No idea if it is or isn't, but it sure looks interesting. Looks a lot like a rock that was in my grandfathers collection so lm curious myself.

Looks like Massive Arsenopyrite as it is a silvery white colour tarnishing to a coppery bronze down the bottom or it could be a mixture of arsenopyrite and iron or chalcopyrite down the bottom.

The top section looks like standard pyrite to me, but the bottom????. Hit some with a hammer and smell the sparks. I've heard that if there's a garlic smell, then it's arsenopyrite. A great indicator for gold - I hear, but just don't sniff too much

I had a google search which suggest it could be pyrite but thought it typically had more of a cubic shape than my rock.Big wave I will try the hammer and sniff. :Y:

Mick Cov said:

G'day everyone.Im regularly over in Perth from Melbourne visiting family and while there recently in picked up this rock which was glistening in the sun on the banks of the swan river.Heavy for its size.
I have noticed boulders used to shore up the banks have heaps of pyrite which looks different to this rock,it's just a solid silver colourhttps://www.prospectingaustralia.com/forum/img/member-images/8894/1499583090_img_3489.jpg

Click to expand...

Gday Mick

See my pyrite
Maybe yours is pyrite

That does look very similar in shape.Where did you find that mate?I have some quartz set in black slate,my daughter loved it and kept it.It did look good though,I will try to get a pic of it.

Mick Cov said:

That does look very similar in shape.Where did you find that mate?I have some quartz set in black slate,my daughter loved it and kept it.It did look good though,I will try to get a pic of it.

Click to expand...

Here in Brazil there is a lot of pyrite
It is very beautiful and very heavy.

The smell from arsenopyrite is pretty unmistakable, I was sitting in my garage one day and found a piece stuck in my tyre tread after a prospecting trip, I pulled it out gave it a tap with a hammer just out of interest and the garlic odour was quite obvious. I think even if you scratch it with something it will release the odour. It's not exactly like garlic but it's an obvious weird garlic type odour.

Nice work Joao.
I tried chipping some away but there is no garlic smell,just a normal flint odour.Just out of interest is arsenopyrite toxic at all?

Arsenopyrite is iron arsenic sulphide, so yeah it is quite toxic. A lot of natural minerals are very toxic.

http://www.chemistrylearner.com/arsenopyrite.html

Ok,thanks Heatho :Y:

pm sent

Looks like at least 3 minerals to me, of differing colours. Get streak and hardness of each, noting colour, then we can guess. Is the top mineral weakly magnetic (pyrrhotite?). Yellow mineral looks like chalcopyrite

G'Day All

Again hard to tell from photos but given it is silvery without obvious crystal shapes I would guess at specular hematite and chalcopyrite. Looks like the ore from the mine I worked on.

araluen

Doesn't have the more flaky form of specular hematite. If it was that the streak would be a giveaway.

Another interesting fact about pyrites is that it's a semi-conductor, so will give a reasonably low reading on an ohm-meter - not a very low reading like gold or silver (< a few ohms), but generally in the range of 100ohm to a few kohms.
I used to use these sorts of minerals as a kid to make the "cats whisker diodes" in crystal sets (if you're too young to know what they are - use google).
If it's a low conductor, then reasonably certain that it's a form of pyrites.

Still interested to know if it is magnetic

I cant find that particular specimen so thats a negative on whether or not its magnetic.
Ill put up a pic of the pyrite crystals set in slate though which I did manage to find.I found it in an old slate quarry while looking for graptolite fossils.