The present invention relates to a method for making boron nitride powder having a thermal diffusivity of from about 0.14 cm.sup.2/s to about 0.20 cm.sup.2/s. This method involves pressing high purity, hexagonal boron nitride having an average platelet size of at least 2 microns into a compacted form, sintering the compacted form of boron nitride to form a sintered body, and crushing the sintered body under conditions effective to produce boron nitride powder having a thermal diffusivity of from about 0.14 cm.sup.2/s to about 0.20 cm.sup.2/s. Another aspect of the present invention relates to boron nitride powder having a thermal diffusivity of from about 0.14 cm.sup.2/s to about 0.20 cm.sup.2/s.