"Crystal" is fine. I've known several girls named "Crystal," it isn't rare. According to the Social Security administration, in 2017 it was among the 1,000 most common names given to girls, although it's pretty far down on the list--#644. "Ruby," "Emerald," and "Pearl" are also in the top 1,000, is on the list. I've met girls named Ruby and Pearl, but never Emerald. "Esmeralda," which is Spanish for "emerald," is also among the 1,000 most common--it's probably popular because of the character in "The Phantom of the Opera."

The Flintstones had a daughter whose name was Pebbles but it is not a very common name in real world English. The meaning of "Pebbles" is "little stones". Did you like the Flintstones on TV ? Did you like cartoons ?

Olivia💙

I have two girl cousins with rock names, Emerald and Sapphire, (or Emmy and Sapphy for short). Other popular rock names for girls, that I can think of, are Ruby, Amber, Opal, Pearl, and Amethyst (Amy for short).

How about 'Ruby'... sounds cool to me...