Pieces of opal derived from erosion of a vertical or level. The term is rarely used in South Australia, but commonly used at Lightning Ridge and refers to opal found in the form of small nodules.

Pieces of round or nodular opal typically found in the Lightning Ridge area. The term is used to describe opal typically found in the Lightning Ridges area. These are the stones that fortunes are made of. It is unusual to find an uncut nobbie (with any promise) as a good nobbie may be worth up to $50,000 and many of these show no indications on the surface.