This appears to be a vintage Etienne Aigner gold-tone horseshoe logo stick pin featuring a polished equestrian-style "A" design.

Etienne Aigner vintage stick pins like this one generally value between $5.00 and $38.00 on the secondary collectors' market.

A few factors determine where a specific pin falls within that price range:

• Condition: All-metal polished gold-tone variations typically sell toward the mid-range ($12.00 to $18.00) if the finish is free of heavy scratches or tarnishing