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Opal — specimen 0227, photo © NMNHS
Opal — specimen 0227, photo © NMNHS

Opalspecimen 0227


Central America
Opal — specimen 0227, locality map

Weight: 1.66 ct; size: 12.18 | 5.57 | 3.79 mm; shape: octagon; colour: medium orangey red; very slightly brownish; clarity: eye clean; cut: fair; treatment: none.

Very clean specimen of ‘fire opal’ variety; step cut style.

Other specimens
Opal — specimen 0376Opal — specimen 0417Opal — specimen 0167Opal — specimen 0412Opal — specimen 0211Opal — specimen 0544Opal — specimen 0722Opal — specimen 0229Opal — specimen 0264Opal — specimen 0461Opal — specimen 0469Opal — specimen 0518Opal — specimen 0713Opal — specimen 0720Opal — specimen 0373Opal — specimen 0557Opal — specimen 0361Opal — specimen 0073

More information from ‘Classification’

Regarded as mineral species for historical reasons; not a true mineral in the accepted sense of the word as it is either composed of cristobalite and/or tridymite or of amorphous silica; sedimentary and secondary from the alteration of high silica igneous extrusive rocks. There are specimens of 2610 carats (Arem, 1987: 139).