Opal Blog - Australian Opal Hunter

Chaff Pattern - Small blocks of color in opal giving an appearance of “chaff”.  Chinese Hat - A nodule (knobby) of rough opal which is formed in the shape of a “Chinaman’s hat”.   Visit only heritage opal site heritage listed , riches opal field on the world wide web www.graham black opal.com   , largest black opal found in modern times Guinness book of records Harleys comet black opal.  Cobwebs - Thread-like impurity having the appearance of open weave knitting.  Copi - A white impurity in opal.      Cotton - Thread-like impurity in opal resembling cotton.     Crack - A fracture in opal which greatly, reduces the value.