Sterling Silver Blue John Marcasite Pearl Frog Brooch. M295. This unique Frog brooch has been crafted from sterling silver and set with stunning cabachons of Blue John. The Blue John stones have been surrounded by sparkling marcasite and seed pearls which give the piece a vintage feel. All our Blue John jewellery is designed and crafted within our very own workshops in Ashbourne, Derbyshire where a team of skilled craftsmen turn the raw Blue John stone into these stunning pieces of jewellery. You can find other matching Blue John jewellery and other Blue John brooches on our website. Dimensions: 5.5 x 3.5cm