Thomas Sabo Charm Club Collection December Birthstone Birthstone by THOMAS SABO: The hand-cut dumortierite is held in star shape by an elaborate claw setting and brings luck to people born in December. Find the perfect match for this little charm in our 'Thomas Sabo' Bracelet and Necklace Collection. Clasp: Lobster Height approx. 2,25 cm )Widthapprox. 1,00 cm