Opal: Mineral information, data and localities.

Although it is still (2007) regarded as a mineral species for historical reasons, opal is not a true mineral in the accepted sense of the word as it is

Opal-AG: Mineral information, data and localities.

Opal - Wikipedia

Opal: The mineral Opal (black, white, fire) information and pictures

Polished Dendritic White Opal Hearts x 8 From Moralambo, Madagascar

Opal Geoscience Australia

Opal, Peruvian Blue - Peruvian Blue Opal is a mystical dream the earth has blessed us with. The energy can vary depending on its locality when dealing

Blue Opal - Andean, Rough

Opal-A: Mineral information, data and localities.

Opal - The Colorful Silica

Gold Opal: Mineral information, data and localities.

Opal, Peruvian Blue - Peruvian Blue Opal is a mystical dream the earth has blessed us with. The energy can vary depending on its locality when dealing

Blue Opal - Andean, Rough

Opal: The mineral Opal (black, white, fire) information and pictures

Rare $675,000 opal makes public debut