The present invention provides a magnetic viscous fluid comprising a magnetic particle, base oil, an inorganic cation exchanger with a siloxane bond, and silicone oil. A difference AB between a solubility parameter A of the base oil and a solubility parameter B of the silicone oil is 1.3 (cal/cm.sup.3).sup.1/2 or more.

Disclosed herein is a lubricant composition comprising a base oil or a fully formulated lubricant; and graphene nanoparticles derived from a carbon containing gas dispersed in the base oil or the fully formed lubricant.