noun \ˈō-pəl\

: a white or clear stone that reflects changing colors and that is used in jewelry

Full Definition of OPAL

:  a usually amorphous mineral that is a hydrated silica softer and less dense than quartz and typically with definite and often marked iridescent play of colors and is used especially as a gem

Origin of OPAL

Latin opalus, from Greek opallios, ultimately from Sanskrit upala stone, jewel
First Known Use: circa 1586

Rhymes with OPAL


noun    (Concise Encyclopedia)

Black opal from Australia; in the collection of the Department of Earth Sciences, Washington …—John H. Gerard

A hydrated, noncrystalline silica mineral used extensively as a gemstone. Its chemical composition is similar to that of quartz but generally with a variable water content. Pure opal is colourless, but impurities generally give it various dull colours ranging from yellow and red to black. Black opal is especially rare and valuable. White opal and fire opal, characterized by yellow, orange, or red colour, are much more common. Various forms of common opal are widely used as abrasives, insulation material, and ceramic ingredients. Opal is most abundant in volcanic rocks, especially in areas of hot-spring activity. The finest gem opals have been found in Australia; other areas that yield gem material include Japan, Mexico, Honduras, India, New Zealand, and the U.S.


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