❓Your Mineral Identification Questions answered here

[Michelle11]

The smelting process creates not only fancy crystal forms like needles but also minerals that are not known to occur naturally. Here are two examples (I don't think either are what you have).

Smelter products often form fine needles - this is caste iron
View attachment 4120

this is lead smelter slag (needles are calcium phosphate)
View attachment 4121
The needles in smelter products usually result from it being suddenly quenched to soild from a liquid state, so it does not have time to crystallize properly.

 

[Michelle11]

Does smelter continue to crystallise many years later?

 

[user 4386]

Does smelter continue to crystallise many years later?

Almost certainly not - I think it would be over in hours at most. Time to nucleate the need;es but not for them to recrystallize. But I'm guessing.

 

[Michelle11]

Almost certainly not - I think it would be over in hours at most. Time to nucleate the need;es but not for them to recrystallize. But I'm guessing.

Hmm ok. Since I have been handling my rock a lot more recently It certainly does seem to have formed more obvious needle like crystals on the exterior.
It is a mystery to me and amongst the many people I have physically shown it remains a mystery to them also.
I Thanku all for ur advice but am thinking
a museum could be my next point of call, just to be sure!
I will although remain open to any other suggestions anyone may have on where else to take it to be further assessed.
Thanku

 

[Capertee gold]

Found these when panning in the cudgegong River about 6 yrs ago any ideas

 

[user 4386]

Hardness is your main clue to differentiate some red stones such as garnet 6.5 - 7.5 and true ruby 9 (very different), Specific Gravity and other properties don't help much. Ruby spinel 8-8.5 is much more difficult to distinguish from true ruby as their hardnesses are closer.

In general, I find that hardnesses above 7 are tricky (quartz is 7, topaz 8, corundum 9, diamond 10). If you can get small pieces of these minerals it is easy, although it is handy to have a pointed edge. I lashed out and bought a hardness testing kit like this:

https://www.mineralab.com/HardnessP... hardness value of 2.5 and 3.5, respectively.

 

[Heatho]

Found these when panning in the cudgegong River about 6 yrs ago any ideas
View attachment 4156

Rubies almost certainly, there are a lot of rubies in the Cudgegong River, quite a well known deposit. Most are small and not great quality but those look pretty good to me.

 

[user 4386]

Rubies almost certainly, there are a lot of rubies in the Cudgegong River, quite a well known deposit. Most are small and not great quality but those look pretty good to me.

Highly likely - plenty of small rubies around Cudgegong. Lots of other things too (eg gold Around Appletree Flat. sapphire). Was surprised to find rounded pebbles of bright red mercury sulphide (metacinnabarite) in a small gully draining into the river from the south (on the Kandos road).

 

[kvan64]

Good day everyone
I was given this stone. It is about 25kgs and I was told it came from South Australia.
Could someone please tell me what you think it is?
Ta

 

[Newprospect]

I’m no expert but it looks like jade.

 

[user 4386]

Good day everyone
I was given this stone. It is about 25kgs and I was told it came from South Australia.
Could someone please tell me what you think it is?
Ta

It might be Cowell jade (strictly nephrite, unlike the valuable Chinese jade that is jadeite)

 

[user 4386]

Hi everyone, trying to figure out what this is.

Detector went nuts when I hovered it over a pile of rocks, moved the rocks and a little bit of topsoil and found what you can see on the top of the picture, split it open to a nice shiny surprise.

I'm thinking it might be Pyrite, maybe?

Any help would be appreciated, thanks.

If it is magnetic it is more probably pyrrhotite. You need to test its properties, photos are not sufficient,. Pyyrhotite tends to be more reddish-bronze than pyrite (which is more yellow), and this looks like pyrrhotite but photo colours are unreliable. The most diagnostic features are that pyrrhotite will pick up a steel sewing needle and pyrite will not, and the hardness of pyrite is 6 to 6.5 whereas pyrrhotite is 3.5 to 4 (very different), Usually a steel pocket-knife blade will easily scratch pyrrhotite but not pyrite (but it depends on the steel a bit as some steel may scratch pyrite). Same with most window glass.

 

[Ed1]

Doing a some earthworks for a house slab and we hit rock, just wondering what type of rock it is, to me it looks like some sort of fine sandy silty clay with some iron in it that has been compressed over the ages, here is the pic of a smallish boulder I hit with a sledgehammer, comes from the Craignish area in Hervey Bay. Nothing of value just a pain in the backside to have to dig up.

 

[user 4386]

Doing a some earthworks for a house slab and we hit rock, just wondering what type of rock it is, to me it looks like some sort of fine sandy silty clay with some iron in it that has been compressed over the ages, here is the pic of a smallish boulder I hit with a sledgehammer, comes from the Craignish area in Hervey Bay. Nothing of value just a pain in the backside to have to dig up.

Probably a siltstone or fine-grained sandstone of the Permian Amamour Beds

 

[ShinyAmy]

Hi everyone is this rock quartz or limestone or something else? Thank you in advance
Amy

 

[user 4386]

If you can scratch it with a dollar coin and it fizzes with acid it is limestone (or calcite). If not probably quartz.

 

[Ed1]

Probably a siltstone or fine-grained sandstone of the Permian Amamour Beds

Thanks Goldierocks

 

[Debbie K]

Hello, all. It's been a while since I've posted anything.

I bought this opal in matrix today and was curious about whether or not it was likely to be Australian in origin. The sandstone it's in is very coarse compared to what I've seen before, and I wondered if it could be Ethiopian, as I have seen some of it in these colors.

The seam appears to go more than half way down the stone, and I was considering carving the sandstone away. Is it worth more as a specimen than it would be as a carving? There's also a thinner seam lower down. Edit: I do know how to carve opal. See photo.

What do you guys think? Thanks for any thoughts.

 

[user 4386]

Hello, all. It's been a while since I've posted anything.

I bought this opal in matrix today and was curious about whether or not it was likely to be Australian in origin. The sandstone it's in is very coarse compared to what I've seen before, and I wondered if it could be Ethiopian, as I have seen some of it in these colors.

The seam appears to go more than half way down the stone, and I was considering carving the sandstone away. Is it worth more as a specimen than it would be as a carving? There's also a thinner seam lower down. Edit: I do know how to carve opal. See photo.

What do you guys think? Thanks for any thoughts.

Impossible to know from a photo. but I have seen plenty here in coarse -grained sandstone

 

[Debbie K]

Are there any particular locales that they are located?

Thanks!

Debbie