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 portrait of him done in miniature under a rock crystal top. Later variations included cufflinks, buttons, earrings, and slides, in addition to the original pendants and rings. Some of these 18th century versions, like this lovely ring, were made in gold and featured a fine hair work background with a lacy gold wire border and initials set beneath the crystal top.