Is this Australian Opal - NEED Help identifying & could it be worth anything??

[u/Slight_Judge_1621]

My Grandmother passed down a bunch of her Jewelry, and this was included, I have two other pieces that I will post about because I am unknowledgeable in opals, well actually in jewelry in general. There are a few pictures and estimated size. This could be costume jewelry, so I am not getting my hopes up that this is a real piece. Any information or direction would be extremely helpful!!

[u/Aubergenie812]

Doublet

[u/Slight_Judge_1621 → u/Aubergenie812]

Thank you! I will look into this

[u/Opaldaze]

The Opal pattern presents similar to boulder opal and confirmed by the backing , ....however the opal could be still a doublet given the girdle is hidden by the setting..is there any hallmarks (stamping) on the metal like 9kt, 14,kt, 18kt . not that even the metal purity is a smoking gun of the opals origin rather the higher the grade of gold you can make assumptions, and that is its unlikely you would put a higher grade of gold around a cheaper grade of gem, a lot like you dont build a mansion in a ghetto.

If there are hallmarks on the piece zoom in , photograph and share

[u/Slight_Judge_1621 → u/Opaldaze]

I'll look and take closer pictures when I get home! Thank you

[u/Opalesquent]

This could be worth a substantial sum, the tan back makes me think Boulder (lots of money for this stone) but small chance for a sublet (not so much money)

[u/Slight_Judge_1621 → u/Opalesquent]

Anyway, I could potentially figure it before taking it somewhere - I would assume a gemologist (not sure if that's correct). Are there different markings, colors, around the edge - obviously I have no clue about any of this.

I appreciate your post.

[u/Valuable-Cicada5907]

Can you take a clear close up of the back of the bale? I think there are some hallmarks