Boulder opal, also known as rock opal, is native to Queensland, Australia. It is found more specifically in the southwestern regions of Queensland. Boulder opal occurs in the form of opal veins trapped in iron ore. It is cut in such a way that a portion of this mineral is left around the opal veins. This means that the carving is extremely delicate due to the extreme hardness of iron compared to the hardness of opal. Boulder opal is especially interesting because the contrast with the rock matrix highlights the opal's multiple luminous interplay of colors.
