opal
silica mineral
opal-CT
opal variety
cacholong
variety of opal
Fire of Australia Opal
998 gram uncut opal mined in South Australia
Flame Queen Opal
gemstone
Galaxy Opal
World's largest polished opal gemstone
hyalite
opal variety
Halley's Comet Opal
large uncut black opal, found in 1986, coinciding with the appearance of Halley’s Comet, found at Lightning Ridge, New South Wales, Australia by the Lunatic Hill Mining Syndicate
wood opal
form of petrified wood
Slocum stone
synthetically grown opal