The types of Opal that i am familiar with are White Opal, Fire Opal, Boulder Opal, Black Opal, Crystal Opal, Light Opal, Doublet Opal, Triplet Opal, Common Opal, Synthetic Opal, and Immitation Opal.

There are 5 basic types of opal. These types are Peruvian Opal, Fire Opal, Girasol Opal, Common opal and Precious Opal.

There are 5 basic types of opal. These types are Peruvian Opal, Fire Opal, Girasol Opal, Common opal and Precious Opal.

An Ethiopian opal is an opal-CT, whereas an Australian opal is an opal-A. The Ethiopian opal is made up of leptospheres, instead of small amorphous silica spheres like the Australian opal.

Boulder opal is distinct from black opal in the following ways: * Boulder opal is usually mined in open-cut operations while black opal is mined in shafts. * Boulder opal is found in ironstone boulders, while black opal is found in seams.