FedeX23さんのイラストまとめ

Bonus round
-Diamond's costume has three stars and one moon for the clip
-Some scans have a more "casual" pin with just two stars
-The fabled single moon and star barrette on the World Tour scan
-Her training hairclip which is just a triangle and I find neat

The anime design has the moons be the same size and in a straight line, and the star is much bigger and on the middle. It fits the simpler anime designs and feels like a real barrette, but loses on a bit of the charm.

Thinking about Kasumin's signature hairpin
Most non-anime visuals (Magazines, SIFAS, 4koma etc) loosely depict it as two rounded moons, one larger than the other, with a small star somewhere on top of the bigger one