Identify these Australian opals?

[Wolfrott]

On behalf of my mother, these 18ct gold opal earrings were purchased in Australia, NT, over forty years ago.

I have no idea how to identify opals, so can anybody help me figure out the type of opal, and quality? The opals are 7mm in diameter.

 

[cm366]

No guarantees from a photo, obviously, but those look like solid white crystal opal to me (solid means they're all opal not a thin layer with a glass or quartz dome, white refers to the base color of the material, and crystal refers to its translucency). There are lots of mines they could've come from, mostly in New South Wales.

If you were intensely curious, I'd do some reading here and maybe ask the owner's opinion:

http://www.opalsdownunder.com.au/learn-about-opals/introductory/crystal-opals

 

[Wolfrott]

Yep, they're solid! Won't catch me within 100ft of a doublet or triplet!

Thanks, I'll try that

 

[aussiejamie]

Hi Wolfrott,
I absolutely agree with cm366 about the type of opal. Coober Pedy is known for producing white crystal opal. In saying that white crystal opal is found in lightning ridge too. I have personally cut a fair few stones that look similar to your gems which were from rough sourced from Coober Pedy. It is hard to give a definite answer though.

 

[Wolfrott]

Thanks everyone, I've got my answer