opal
A mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity, of the chemical formula SiO₂·nH₂O.
Noun
- A mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity, of the chemical formula SiO₂·nH₂O.
- Although there are dozens of different types of gems, among the best known and most important are […] . (Common gem materials not addressed in this article include amber, amethyst, chalcedony, garnet, lazurite,...
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(gemology) A precious gem, an iridescent gemstone found in the opal-silica mineral substrate (potch)
- The colour of opal: any shade of blue with bright flecks of other colours, such as white, yellow, and red.
- The witchery of the dawn turned the grey river-reaches to purple, gold, and opal; and it was as though the lumbering dhoni crept across the splendors of a new heaven. - 1889, Rudyard Kipling, “Only A Subaltern”, in...
- A colloquial name used in molecular biology referring to a particular stop codon sequence, "UGA."
- Any of various lycaenid butterflies of the genus Nesolycaena.
Origin
In Florio’s A World of Words 1598 as opale, from French opale, from Latin opalus, from Byzantine Greek ὀπάλλιος (opállios), from Sanskrit उपल (upala, “gem, stone”), from उपरि (upári, “the upper millstone”). Distantly related to over.
Forms
Derived
black opal boulder opal chloropal fire opal Grawin Opal Fields jasper opal opal aura opaled opalesce opalescence opalescent opalesque opaleye opal glass opalic opaline opalise opalish opalize opalotype opal pineapple opal pseudomorph Opalton opalware