Sterling Silver Blue John Marcasite House Style Dragonfly Brooch. M328. Complementing our sterling silver and enamel designs, the introduction of sparkling and natural marcasite stones provides a classic and elegant way to accessorise any outfit. With a certain Art Deco feel, accompanied by Derbyshire Blue John and Garnets, the collection features wonderful insect earrings, brooches, rings and pendants. This eye catching dragonfly brooch is hand made in Sterling Silver and features a beautifully hand carved Blue John gemstone set in the body and sparkling Marcasite gemstones set in the wings and tail. The Blue John stone has been directly sourced from Treak Cliff Cavern in Castleton. Dimensions: 30mm x 30mm.