Matthew Calvin Octagon Bolt Ring - GoldA classic, geometric shape, the Octagon Bolt Rings were designed in Matthew Calvin's signature minimalist style. Made in Sterling Silver, Gold or Rose Gold Vermeil, these high polish rings are perfect for those of you that love minimalism, but want eye catching, statement making pieces. Retaining the same creative simplicity as our other collections; solid, study and hand finished, the pieces within the Essentials collection feature geometric shapes