Opals are sparkly, sumptuous, sorrowful. This association makes me like
Opal - which is by no means an attractive sound - slightly more.
Opaline is sillier, heavier, more like an adjective.
masculine list:
https://www.behindthename.com/pnl/191050/124079feminine list:
https://www.behindthename.com/pnl/191050/124080