Diamond Earring Woman
An attractive, self-sufficient, experienced "older" woman (over 40) who is able to buy herself diamond earrings, i.e., she doesn't need anyone else to do anything for her. These women usually attract younger, submissive men or women. Also, a domineering woman (which is the word that was misunderstood as "diamond earring" that led to this definition).
I always seem to end up with a diamond earring woman!