light opal
crystal opal
boulder opal
boulder matrix opal
black opal
composite opal
This variety includes opal which is transparent or very translucent and in better qualities shows a distinct and very bright range and play of colours. Light crystal opal generally comes from South Australian opal fields.

Black crystal opal is found in the Lightning Ridge fields, this type has a smoky colouring, which the light crystal opal does not have.