Is “Opal” a Scrabble word?
Yes
OPAL
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Opal
/ˈəʊpəl/
noun
1.A mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity, of the chemical formula SiO2·nH2O.
2.A colloquial name used in molecular biology referring to a particular stop codon sequence, "UGA."
3.Any of various lycaenid butterflies of the genus Nesolycaena.