Sterling Silver Blue John Marcasite Four Stone House Style Butterfly Brooch. M326. 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 butterfly brooch is handmade in sterling silver and features four beautifully hand carved marquise shaped Blue John gemstones, sourced directly from the Treak Cliff Cavern in Castleton, which are surrounded by a silver frame accented with sparkling Marcasite gemstones. Dimensions: 24x35mm.