If there is 'One' black gemstone, it's Onyx, a Black Agate, Chalcedony variety of Quartz Sterling silver Celtic Triquetra knot rings embody mother, maid, crone of the three faced pagan Moon Silvershake 8mm Natural Round Shape Black Onyx 925 Sterling Silver Triquetra Celtic Knot Solitaire Ring, is shipped with anti-tarnish protection in reinforced gift boxes & satin-style pouches; guarantee far-outlasting competitors Onyx, banded chalcedony, has been used for engraving since Roman antiquity; the relief effect of cameos achieved by carving out one level of material and contrasting it against the other behind Silvershake 8mm Natural Round Shape Black Onyx 925 Sterling Silver Triquetra Celtic Knot Solitaire Ring Size 7