Definitely not green glass...

No silver but not glass

 

Labradorite, maybe. But can't really see it.

 

Pretty sure it's labradorite. Is there more play of color, little flashes here & there, than photos are picking up?

 

It's definitely stone, I can see the inclusions, I tend to agree on Labradorite.

 

Structure is wrong for Labradorite.Shine a light through it as there appears to be air bubbles.

 

It looks like obsidian to me, possibly blue, I think the yellowish background is deceptive. Estater, is the stone blueish against a white background?
Obsidian is volcanic glass. It occurs in different colours.

Blue obsidian:

 

The colored "obsidian" is man made glass,China has been producing tons since the 90's for New Age,etc shops.............. https://www.gemsociety.org/article/obsidian-jewelry-and-gemstone-information/

 

Maybe green tourmaline?

 

Flourite?

 

I am sure they have, when there's a market, they will make or fake it. Mt St Helens obsidian can also be blueish to green and is also manmade, after an accidental occurence.
On the other hand, this site mentions blue as one of the obsidian colours, albeit rare:
https://geology.com/rocks/obsidian.shtml

I have no idea if the one I posted is genuine. If Estater's pendant has bubbles, as you said, it could be the man made obsidian you mentioned.