Abstract: A silicate phosphor composition is provided having a ?-phase of an orthorhombic crystal structure whose space group is Pbnm 62, and whose composition is represented by the following chemical formula: Ca2-x-y-zMxSiO4:yCe3+,zN(0?x<0.5,0<y?0.1,0?z<0.15) In the formula, M represents at least one member selected from the group consisting of Mg, Sr, Ba, Zn, Na, Al, Ga, Ge, P, As and Fe, and N represents at least one member selected from the group consisting of Eu2+, Mn2+, Tb3+, Yb2+ and Tm3+. The silicate phosphor has a maximum absorbance for a wavelength of about 450 nm to about 475 nm corresponding to a main part of a blue excitation light, and has a great stability at a high temperature. As such the silicate phosphor may be used in combination with a blue light source to produce a white light.