I've got a white opal necklace that's been in the family since before the First World War, and yes, it is lovely. But I dislike gem names in general; can't think of one that I'd use unless you count
Coralie (but not Coraline or
Coral).
Opal wants to be a joke or cartoon name -
Olive Oyl,
Opal Otter,
Pearl Persimmon, that kind of thing.