Some kind of pendant not sure what it is help identify?

Operculum https://chatsworthlady.com/2016/04/06/antique-victorian-operculum-jewelry/

 

I think it's a bit of shell. Maybe the tip off a conch.

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Ok. What Marie Forjan said.

 

Depending on size and quality,they sell for around $4 a dozen.

 

Hi,
Marie hit right on the nose.
greg

 

Kingjoker, thanks for showing that pendant. I never knew what the BACK of operculum looked like.

I have a steel bracelet, made in the Pacific theatre during WWII, that was given to my Mom way back when. The "stone" was identified for me as operculum on another forum (very possibly by Marie!) a few years ago, but the back of the stone isn't visible on my bracelet:

 

that's pretty nice engraving for steel !!

 

It could be something a sailor picked up on leave in Australia. I'd personally guess it was the work of someone on board ship with time to kill and access to the proper tools. There were some guys out there somewhere with engraving training.

 

I have an operculum, or cat's eye, pendant set in 18k gold in Finland in the 1930s.
I always wondered how it got there, suppose it was a sailor. They must have thought it was rare and therefore valuable, to put it in a gold mount.