BLUE TOPAZ RING in Silver. This is a beautiful, eye catching, ring, a 10×8 mm quality faceted Blue Topaz gemstone set into our bespoke design. With a good sized band, 4.6-5mm wide, and 1.2mm thickness, this ring feels very comfortable on the finger. Blue Topaz is the birthstone for December. Blue Topaz has always been known as being a symbol of love and adoration. This ring is size 58 (or Q), it weights 7.8g and the stone weights 3.3ct and it is a 10mm x 8mm oval.