Patent ID: 8507414

Claim:
An oil-in-water (O/W) emulsion composition comprising ultrafine diamond particles having an average particle size of 100 nm or less, which is treated with a water dispersion dispersant and/or an oil dispersion dispersant, and wherein the ultrafine diamond particles are dispersed in a water phase (W phase) and/or an oil phase (O phase), wherein the ultrafine diamond particles are added and dispersed (1) in the water phase (W phase) as a dispersant-treated ultrafine diamond particle water dispersion prepared by treating the ultrafine diamond particles with a water dispersion dispersant and/or (2) in an oil phase (O phase) as a dispersant-treated ultrafine diamond particle water dispersion prepared by treating the ultrafine diamond particles with an oil dispersion dispersant, wherein the ultrafine diamond particles in the dispersant-treated ultrafine diamond particle oil dispersion (2) are ultrafine diamond particles which have a water dispersion dispersant and an oil dispersion dispersant.