Opal 925 silver boulder necklace - 22.5×6×18.5 mm - 9 g

Natural premium quality boulder opal with 925 silver necklace. Among the natural opals there are three types whose variety depend on two features: background colour and transparency. These include the opal gemstone, the so called matrix opal, and the boulder opal. The latter occurs in one piece where the opal (with extremely vivid and bright colours) is of course combined with a rock which it has formed in (hence its name) . The rock on which the opal lies has a different chemical composition. The layer of colour is naturally cemented to the stone on which it lies: the two elements are inseparable. These opals are from Queensland and are unique in Australia.