Abstract: A liquid suspension for planarizing an outer surface of a material comprises a liquid suspension medium of a specific liquid density; and a plurality of solid, contact-sensitive abrasive particles of a constant solid density and suspended in the liquid suspension medium. The liquid and solid densities are approximately the same so that the abrasive particles freely and stably suspend in the liquid suspension medium, without gravitational separation by settling down or floating up. In this way, damaging contacts of the solid abrasive particles with one another are minimized.