Here is a choker style necklace with 5 shaped crystals that may be of a type of agate or to look like an agate crystal

The crystals are not glass but may of been treated to colour.

The necklace chain is of a gold plated snake link

There is a metal tag on the adjusting chain that has the initials WS - I have not been able to identify who the maker is but I am assuming was perhaps originally purchased from a department store