It is to accessorize their outfits, and to compliment their red socks. Now, the ones who wear the pearl necklaces have their own locker rooms and showers. They are especially fond of Bette Midler and show tunes.
Those are called headpins. You can get inexpensive (not high quality) ones at Michaels or other craft store. If you want to make higher quality jewelry, I recommend one of these online sites to get your findings: www.artbeads.com www.fusionbeads.com ...
what kind of pendants are you looking for and what are your goal price and your buying quantity? if you want to buy them in bulk from china, you can contact me for that.