A dielectric ceramic essentially in the form of an aggregate of crystal grains each having a ferroelectric core enclosed in a paraelectric shell. The shells are created by thermal diffusion of magnesium into the crystal grains. Through control of the firing temperature and time the thicknesses of the shells are confined in the range of approximately 5-30% of the average grain size. The resulting ceramic is low in dielectric constant and favorable in temperature characteristic of capacitance, making it suitable for use in laminated capacitors.