Need some help identifing this stone

[nuggethill]

I've been buying bulk stone from different collectors around Australia and this came with a consignment of stone

I have no idea what it is but my guess is Obsidien

I'll post two more

[nuggethill]

Just two more

Thanks in advance

cheers

[nuggethill]

Also this one

I have no idea what this is

cheers Harry

[shivan]

The first stone reminds me of flint in the first photos, but does look a little more like obsidian in the next photos. Is the whitish stuff around it chalky?

The second stone i could only guess at, maybe a schist or adventurine. Will a knife scratch it?

[nuggethill]

It's a lucky stone cut length ways and yes I'd say olivine or adventurine

cheers mate

[nuggethill]

I found out on another site that

this one's chert

cheers all

[shivan]

Flint is a variety of chert that forms in sedimentary rocks like limestone or chalk. That's why i was asking if the whiter stuff was chalky.
I have a big lump ill post a photo of later.

[nuggethill]

This one Ian the whiter stuff is like glass the edges brake off like flint  (chert didn't cross my mind) that's why I thought it was obsidian

so now I know I was mistaken

I also have what looks like salt but zebra pattern and very light weight looks like lime so I'll post a photo latter today  

cheers mate

[nuggethill]

This has got me stumped as I'm not sure what this is

it's light weight

Lime or salt maybe flint very light and brittle

regards Harry

[shivan]

Does the stone have a soapy feel to it?
Except for the lines through it, it looks similar to talc, but whilst talc is soft, its not really light and brittle....
Is the stone a solid mass or made up of granules or crystals?

If it were a halite (salt) you should be able to see some cleavage planes and if you lick your finger and give it a rub it will start to dissolve the stone, plus you should be able to scratch it with a fingernail.

Maybe a limestone like chalk i guess would be light and brittle, could be a good candidate.

[nuggethill]

Thanks for the comment Ian

A bloke on another site said he has a piece of this stone and it's from Cooper Pedy and still we didn't nail it down

Cooper Pedy = limestone I think 

P.S. Ian I've just brought or had to buy a Lortone BA64 only a 6"4 wheel crabber I couldn't change the wheels on the Gemmaster

I really didn't want to buy it but had to if I want to keep carbbing

cheers Harry

[shivan]

Yea i think i remember reading about the limestone dumps at Coober Pedy, so if limestone the white is most likely calcite and the darker layer aragonite i believe. If you want to find out for sure and have any diluted hydrochloric acid (5-10%) for cleaning bricks or concrete, put a drop on the rock and it should start fizzing if its a calcium carbonate.

What problems were you having getting the wheels of the Gemmaster? We have a lot of the two wheel gemmaster setups at the club so i may be able to see if they have had any problems.

[nuggethill]

It's a combo mate and I can't get the nut off the saw end it just won't budge ended up stripping the edges of the hexagonal brass nut both sides

I needed to change the grinding wheels and couldn't so much easier to buy a new one

for sale very very cheap

one gemmaster combo LOL

cheers Ian

[shivan]

Ahhh its the same one i have. I use a pipe wrench on mine with a shifter or holding the grinding wheel with my hand. If you don't get anyone interested in it let me know as i may be interested in it for parts.

Your new machine looks like the bees knees though, will you be using 6" or 8" wheels?

[Flying Scott]

I have a couple of them . I would say you have Volcanic glass, Otherwise known as obsidian.
You could make great cabochon.
Flying Scott