These unique earrings are Boulder Pipe Opal. Pipe opal is formed by tubes or pipes of opal occurring in the sandstone. The theory is that type of opal formed millions of years ago when organic matter , such as twigs and leaves , disintegrated leaving cavity’s that the liquid opal has filled. The natural formation allows us to create gorgeous unique organic opal jewellery. These opal earrings have glowing bright green colours sparkling from the natural tan coloured sandstone, they are set with high quality anti tarnish sterling silver. They measure 37mm in entire length with the opals alone measuring 17mm x 7mm.