Cairngorm
Cairngorm, (also called Scottish topaz or smoky quartz), a smoky, yellow-brown variety of quartz. It is named for the Cairngorm Mountains of Scotland. The stone is highly prized in Scotland and is used for various ornamental purposes. Its value depends on transparency and shading. The mineral has been found in Great Britain, Siberia, Spain, and Switzerland, and near Pikes Peak, Colorado.