july is the month of passion and power, and what better way to channel its vitality than with a birthstone charm? our serendipity july birthstone charm is charged with the power of ruby. ruby is said to promote passion, strength, and vitality. add it to your favorite necklaces and bracelets to embrace the energy of life. this charm fits over most necklaces and the internal diameter is approximately 2.8 x 2.2 mm.