Another of my best friend's favorite stone, the bright and cheery orange and red of carnelian is definitely enchanting. Orange is the color of happiness and red is the color of passion. This stone truly encompasses both.
Often considered a stone of protection, carnelian is actually a red form of chalcedony. It was worn in ancient Egypt to still anger and jealousy. It also counteracts negative thoughts.
Carnelians are most often worn by those who are a bit more timid to promote courage. It brings out self confidence and can also attract people to you. Its also said to promote sexual impusles. RAWR. ;)
I normally use carnelian in cabachon form. I think this is the best way to see its agate like variations, which I find VERY appealing. I also use small carnelian beads to enhance the look of paler stones, like moonstone.