Boulder Opal is found only in Western Queensland, Australia. They are quite rare as they combine the beautiful colors of other opal but are mixed with ironstone. The combinations of form and pattern are endless. The ironstone adds strength and complex design features to boulder opal as well. The opal is found in the cracks and fissures running through the host rock of ironstone. I take these pieces and cut away the host rock to find the biggest, most colorful pieces of the opal that are trapped inside. No two are alike. These are truly one-of-a-kind pieces.