Carnelian is a form of quartz which is usually reddish orange, although it can range from orange to ruby red. It varies from opaque to brilliantly transparent.
Carnelian was believed to give courage to speak boldly and well. It is particularly revered by Muslems because Mohamed wore a silver ring set with a carnelian.
Carnelian was often used in jewellery, especially cameos, and was also widely used for seals because wax does not stick to it.