Man Made?

Can anyone identify this material I bought at a show a few months back?
I think it is man made and seems to be a bit porous.
When wet it displays blue and green colour like you might see in opal.
A club member thought that it would need to be soaked in something to seal it before cabbing.
Chiron.

Could you please put an image of when it's wet as this will give a better idea, thanks - Jack :Y:

Sorry about the glare off the water.
I had to place them IN water as the porous nature of the stuff made it difficult to get a shot of.
Cheers.



Er, yes I paid $8 for the small piece. :8

Fairy Opal.... Man 'Enhanced'..... a bit on Fairy Opal.. :Y:

https://www.prospectingaustralia.com/forum/viewtopic.php?id=20825

LW.....

Yes, from your description I thought it could be Andamooka Matrix Opal or fairy opal. And it is!

Fairy opal is the same thing as Andamooka matrix - treated sandstone opal, but the fairy is from a different locality than Andamooka.

Also, Not man-made, but it is treated by sugar.
Great find! - Jack :Y:

Mistake I made:
Andamooka opal is usually an opalised limestone and fairy opal is usually opalised sandstone. So they are different in that way but are in the matrix opal family. - Jack

Although the 2nd pic makes the stones appear to have a course texture, they are in fact very fine grained.

It might possibly be Andamooka matrix as limestone usually is made up of finer particles, compared to sandstone. - Jack

Since you guys put me on to Matrix opal I have spent a couple of hours with Mr.Google.
After looking at numerous images and reading volumes of text, it would seem my pieces could be either Andamooka or Fairy, depending on what article you read.
But at least I now have a fair idea what they are.
Can I assume that because my pieces have a very dark grey base colour, it means they have already been sugar treated?
(I also notice that my smaller ($8) piece is much more porous than the larger piece.)
SO, in January when our local club opens its doors again I will attempt to cab a piece of the larger slice.
Watch this space for the results.
Thanks Jack and LF for your assistance.

Yes, it depends on where it was formed.
It's dark because it has already been treated.

Don't cut too deep as the colour will go back to white and loose the treating. This will make the colour become barely visible.
Good luck with cutting! :Y: - Jack

Like only a couple of mm deep!

Cheers Jack. I will TRY to be careful.
Although I sometimes find myself being a tad heavy on enthusiasm and a tad light on care.