Try
Herff Jones. They are a Sigma Chi Licensed Vendor.
Lavalieres & Pendants
Sweetheart Jewelry / Gifts
I am partial to the Mother-of-Pearl pendant.
Formerly presented most often to House Mothers and chapter sweethearts, this genuine Mother-of-Pearl pendant has become extremely popular among undergraduates, worn on a neck chain or rawhide cord. The riveted bail loop at top allows for a fairly substantial chain or neck cord to pass through it. Enameled crest center.