That is a vintage green jade or jadeite stick pin mounted on a display card. 

The piece features a smooth oval cabochon green stone set inside an intricate openwork, wire-scrolled gold-tone filigree head. This specific open-wire style was widely popular for costume and estate jewelry items throughout the mid-20th century

The estimated market value for this type of vintage costume jewelry stick pin typically ranges between $10 and $25.

Because it is presented on a standard commercial display card labeled "GENUINE STONES" rather than being house-boxed by a luxury jeweler, it is generally recognized as a mass-produced, mid-century fashion accessory.

The main factors that determine its placement within this value range include:

• Metal Composition: These pins are primarily made of gold-toned base metals or brass. If the pin shaft has a tiny engraved hallmark indicating it is 12K Gold Filled (12K GF) or Sterling Silver, the value leans closer to $25 to $40. 

• Stone Quality: While the stone is a genuine mineral (likely Nephrite Jade or Green Aventurine), it is a standard commercial-grade cabochon cut rather than fine, translucent Imperial Jadeite.

• Condition: Retaining the original display card adds modest value for collectors who appreciate untouched vintage packaging.