opalesce
/ˌɒpəˈlɛs/ or /ˌoʊpəˈlɛs/Definitions
1. verb
to form a rounded spot or patch, especially on the surface of something.
“The patina on the statue began to opalesce with age.”
2. noun
a rounded spot or patch, especially on the surface of something.
“The opalesce on the marble was a beautiful work of art.”