The Bifrost Shard is a radiant, crystalline fragment of the mythical rainbow bridge, glowing with an ethereal, multicolored luminescence. Its form is jagged and irregular, resembling a piece of shattered glass with sharp, angular edges that catch and refract light in mesmerizing patterns. The surface is smooth yet subtly textured with faint, runic engravings that pulse softly with magical energy, hinting at its divine origin and powerful connection to the realms.