Butterfly necklace green

Large 3cm x 3cm  plated Butterfly, with 18inch chain and unusual piece of sea glass. This piece of sea glass was found near the Forth Bridge South Queensferry across the road from the Hawes Inn where Robert Louise Stevenson wrote "kidnapped", in 1866. This sea glass may have been from a old bottle thrown into the sea while working on his book. The mystery of this seaglass is in it's history.