Spikenard is one of those essential oils with a lengthy traditional usage, and is mentioned in the Bible almost as much as frankincense and myrrh (about which another day). It is a variety of valerian which grows extensively in the Himalayan regions, and the oil is derived from steam distillation of the crushed rhizomes. It is an intensely thick and musky oil, which is rarely used in perfumery, as the same effects can be provided with cheaper ingredients.
It was costly even in Biblical times which was why the disciples complained about Mary Magdalen using it to wash Jesus Christ’s feet (Matthew 20:2). Aside from its perfume and incense qualities, it is also used as a sedative and relaxant, and has been used to treat insomnia. However, since ancient times it has been used to anoint the dead prior to funerals; Achilles uses it to anoint the body of Patroclus in the Iliad and it is an essential ingredient in the Tabernacle incense used in Orthodox Judaism.