The object of the present invention is to provide a phosphor which is excellent in transparency, light transmittance, luminescence efficiency and luminescent intensity and at the same time, processes for producing the phosphor. Preferred embodiments of the invention include a phosphor characterized in that phosphor particles represented by the general formula [(L).sub.a(M).sub.b(N).sub.cO.sub.d:Y] are covered with an organic compound bearing at least one functional group at a terminal or side chain, wherein L is a metallic element such as Zn; M is a metallic element such as Al; N is Si or Ge; O is oxygen; Y is at least one activating agent such as Mn.sup.2+, Eu.sup.2+, Cu.sup.2+ or Yb.sup.2+; and a, b, c and d are each a value satisfying the relationships 0