Fluorite is a brittle mineral. It is a soft stone that is also sensitive to impact. You should take special care when wearing this ring to ensure it lasts a long time. It is open on the underside. The stone, including the setting, measures approximately 23 x 17.8 mm. Height: approx. 7.1 mm (8 uneven surface) Size 59. However, the ring band is open/adjustable to some extent, approx. 5.8 mm wide, 1.6 mm thick (8 (domed)).