K18 Boulder Opal Ring

 
 
Boulder opal is a type of opal mined in northern Queensland, Australia. The name "boulder opal" comes from the fact that it forms in the gaps of iron ore deposits. Because the stones are found in very thin layers, only the thin opal layer is cut.
 
 Depending on the color and luster, they can sometimes fetch a higher price than black opals.
 
 The color and pattern are almost the same as black opal, but because the part with the opal attached is cut, the shape is very unique.