This is a 12kt gold-filled earring and apple green Chrysoprase pendant set.
The pendant is a 10mm x 8mm cabochon Apple Green Chrysoprase set in a filigree 4-prong setting on an 18" chain.
There is also the matching pierced earring settings to mount 2 cabochons at 7mm x 5mm.
The back of the pendant setting is marked 12/20 GF.
Chrysoprase is a gemstone variety of chalcedony and is in the same family as agate, carnelian, and onyx. It owes its color to nickel deposits in the crystalline stone and has a Mohs hardness scale rating of 6-7 which makes it very wearable.
This set was part of a jewelry artist's stash that has been liquidated.