Amethyst wedding rings

Amethyst

— a mineral that is a variety of quartz and is distinguished primarily by colour — usually a blue or lilac hue. In addition to natural ones, artificial amethysts are also used — cubic zirconias (see the relevant paragraph), which were given the desired colour.

By itself, amethyst, even natural, is relatively inexpensive, while it looks good. But for wedding rings, a stone of this colour is not quite traditional, and therefore such inserts are rare.