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
Recent Examples of opal from the Web
Glowing like opals under the midday sun, these salt-crystallizing ponds stretch across 27 square miles on the coast of Western Australia near a tiny, remote town with the curious name of Useless Loop.
Lightning Ridge is known for its dark opals, and the opalized plant and animal fossils in and around its mines.
Lightning Ridge opals have been mined since about 1901.
And a tentacle seems much less menacing when set with fire opals, rubies, and diamonds.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'opal.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
Origin and Etymology of opal
Latin opalus, from Greek opallios, ultimately from Sanskrit upala stone, jewel
First Known Use: circa 1586See Words from the same year
OPAL Defined for English Language Learners
Definition of opal for English Language Learners
: a white or clear stone that reflects changing colors and that is used in jewelry
OPAL Defined for Kids
Definition of opal for Students
: a mineral with soft changeable colors that is used as a gem
Seen and Heard
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