Center Stone:Approx.5 mm    <br />Size:This sterling silver Halo ring is available in sizes 6-9<br />Diameter:The diameter of the size 6 is approx. 16.5   mm.The diameter of the size 7 is approx.17.3 mm.The diameter of the size 8 is approx. 18.1 mm.The diameter of the size 9 is approx.18.9 mm.  <br />This sterling silver Halo ring comes in a variety of sizes to fit just about any woman's hand.    Please allow slight deviation for the measurement &real colors compared with the one shown on website.