Stuart crystals are faceted rock quartz crystal jewels which originated as a form of mourning (or protest) jewelry after the execution of King Charles I of the House of Stuart in 1649. The first Stuart crystals were pendants or rings and featured the initials of the king or a miniature portrait of him under a rock crystal top. Later variations included cufflinks, buttons, earrings, and slides in addition to the original pendants and rings. Some of these later versions, like this lovely ring, feature initials within a lacy frame of gold thread over a ground of fine hair work and foil. The underside of the head features the fluted detailing frequently seen in Stuart era jewelry and has retained most of its original enamel.