Compositions comprising inorganic particles

loccular compositions comprising ultrafine inorganic particles having maximum particle dimensions of from 0.5 to 3000 (preferably 2 to 1500) nm combined with a size-stabiliser which is a lyophobic substance with lyophilic activity on its surface and also comprising a polyelectrolyte flocculating agent attached to the combination. The size-stabiliser protects the ultrafine particles against agglomeration during formation of the flocculates and the mixing of flocculates into various materials such as plastics, inks, paint or refractory materials. Also a method for making the flocculates from colloidal dispersions of particles, size-stabilisers and flocculating agents. The flocculates are particularly useful with particles of metals of the coinage and transition groups for making transparent colouring agents. Also materials containing the ultrafine particles.