Abstract: A cation-treated silicate phosphor and fluorescent lamp made therefrom are provided wherein the 100 hour radiance maintenance is significantly improved. The cation treatment method involves adding an amount of a silicate phosphor to a salt solution containing a cation wherein the ratio of cation to phosphor in the solution is from about 1:2 to about 4:1 moles of cation to moles of phosphor. The solution is then stirred for a time sufficient to cause the cation to attach to the phosphor surface to form a cation-treated phosphor. The cation-treated phosphor is separated from the solution and annealed at a temperature and for a time sufficient to increase radiance maintenance of the cation-treated phosphor.