noun馃敆ShareA mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity, of the chemical formula SiO2路nH2O."My aunt collects beautiful opals, admiring their shimmering colors despite knowing they are softer than quartz and can scratch easily. "mineralgeologymaterialsubstancescienceChat with AIVocabulary GamePractice Reading
noun馃敆ShareA colloquial name used in molecular biology referring to a particular stop codon sequence, "UGA.""In genetics class, we learned that "opals," or UGA stop codons, signal the end of protein synthesis. "biologybiochemistrytechnicalChat with AIVocabulary GamePractice Reading
noun馃敆ShareAny of various lycaenid butterflies of the genus Nesolycaena."While hiking in the rainforest, the butterfly enthusiast excitedly pointed out a group of opals fluttering around a flowering bush. "animalinsectbiologynatureChat with AIVocabulary GamePractice Reading
