Australian pipe opal

• A pipe opal is a precious Australian opal having formed in roundish or tubular holes in the mother rock, usually sandstone, but can be also found in boulder.
• Most of pipe opal found is crystal opal with bright colours.
• It is found exclusively in Queensland, Australia.
• It is cut with leaving a layer of sandstone attached to the back of the opal ( as a layer of ironstone is left on the back of a boulder opal).
•When cut and polished, by world standards, It is a "Natural opal,Type 1" if no backing is left,
• or "Natural opal, Type 2" if some of the mother rock is left on the back of the opal.