Maker's Hallmark On This Ring

These two rings has a hallmark of the letter C in a shield. Anyone know who that is? Also was wondering if anyone might know what stone this is?

 

Sorry can't help with the mark or the stone.

Can only say that the ring settings look to be a stamped metal, so not very expensive. The way the bezel fits the stone, makes me think of souvenir type of jewelry, or things a lapidary group might use to set the stones they cut.

That's much help, sorry.

 

For the stones I'd say chrysoprase.
I'm with cluttered on the ring, not top quality, stamped metal.
The mark is a manufacturers mark. Others may recognize it.

A hallmark is stamped by an assay office on items made of precious metal as legal verification of their fineness.

 

Many thanks to both of you. And thanks for the clarification on hallmarks versus maker's marks.

 

I have never seen an adjustable ring that would qualify as fine jewellery or even designer costume. The verdigris visible in the 5th photo indicates the presence of a fair amount of copper. I am inclined to think the stone is glass. The wear to the finish shows someone has loved & worn this very pretty ring.

 

Josh, another detail, a maker's mark usually refers to handmade items. These rings were not handmade.
I would call this a manufacturer's mark, but we have members who know costume jewellery, which I know next to nothing about. They probably know the right term.