From the experts:
Cassia is one of the rare names that's truly unusual yet has a stylish feel. Cassia has the added attraction of the sweet smell of cinnamon; a cassia tree or bush, which has yellow flowers, produces a spice that can be a substitute for cinnamon. We predict Cassia will become much more popular along with her brother names Cassian and Cassius.
Keziah, the Biblical equivalent, is also due for rediscovery, while Kassia is the Greek spelling that ties the name to Saint Kassiani, a feminist heroine.