Early 20th Century Kestenman Brothers Sterling Art Deco Brooch/Pin With Stone

This is a lovely sterling silver filagree pin/brooch, made by Kestenman Brothers, Providence, RI circa 1922-1934. Providence was a Mecca for fine silversmiths including Gorham. Very few pieces made by Kestenman are generally available, this was my grandmothers. A tiny bit of tarnish, otherwise in superb condition. Marked KB with arrow logo on underside. Unsure of what the stone is, but I believe it is agate. It is a seafood blue green, the color of aventurine. It is a nice smaller size , perfect on a hat, lapel, with fine detail with ribbon design. It is small enough for a child/teen to wear. 1 1/4" diameter