FMF - Friends of Minerals Forum, discussion and message board

[barbie90]

Hello everybody ,one of my friend from turkey shared picture of the minerals that he found ,it took my interest because the colours of them are really attractive at first ı couldnt know what they were but later when ı take in acount of their shapes ı thought they were chalsedony or opal but he doesnt want to accept the idea ,he said his stones are so precious ,there are no stones in the world like them he thinks ,what do you think they are?

[crocoite]

Looks like coloured glass...

[alfredo]

I agree. Looks like glass.

[barbie90]

he even got angry to the idea that theyre chalsedony so ı musnt tell him they are glass:;)its so funny

[GneissWare]

GLASS.

[trtlman]

glass for sure looks like they might have been collected from a beach, beach glass is a common find, it's just broken glass pieces from bottles, floaters or other garbage that get tumbled into pebble shapes, also broken glass could be tumbled into pebbles flowing down a river or creek as well, but yeah I am going to agree with everyone else that these are in fact glass fragments.

[barbie90]

ı really want to thank everyone who helps in this forum ,everyone is really helpful ,ı want to thank jordi fabre for making a beautiful and helpful forum,ıt makes me connected to the stones ı got knowledges ı love seeing people like me

[cuperson]

obsidian maybe ?

[mihailovici79]

look like an obsidian....

[Maxilos]

Glass

[lluis]

Yes, glass

And yes, obsidian is a natural glass.
But those chunks are man made glass.

Sorry

With best wishes

Lluís

[cuperson]

How do you figure ?

[John S. White]

Definitely man-made glass. The colors are typical of man-made glass, not of obsidian, and the transparency is also typical of man-made glass. Also, I believe I can see air bubbles in the glass which is a clincher.

[lluis]

Hi, Cuperson, List

I will place in another way.

Find an obsidian chunck that is colorless, and I will think that maybe I am wrong.

All obsidian I have seen is black as sin, and not a chunk I have seen has bubbles.

Then, corolarium is that the nice colored chunks are manmade glass.

Besides, to be obsidian, they should be found near an old (or modern, if you like risks) volcano....

Myself, I have seen when young (yes, in the Jurasic....), a piece of a dark colored glass that should be manmade because in Barcelona city never has been a volcano.

Hope it serves

With best wishes

Lluís

[weaver]

There's no crystal structure in those specimens either. I don't see anything geometric, with the exceptions of some of the fractures. Most of the fractures appear similar to the way glass breaks. Also, when there's no "larger" specimens (or specimen variety in size/length), I tend to question the origins.

Do you suppose obsidian is always black due to the [volcanic] heat under which it forms? Nerp... just looked it up, it's the mineral content: iron and magnesium. With minimal research it seems that transparent obsidian is in question, which means "colored, transparent" obsidian is probably also suspect.

As for your friend, just tell him he's got a collection of:

Amorphous (non-crystalline) solid material comprising of mostly silica (SiO2) plus Na2O, CaO


But don't mention it's glass ;)



Excellent note about the air bubbles.