What is that which is used to render white; whiting. [R.] Whitening stone, a sharpening and polishing stone used by cutlers; also, a finishing grindstone of fine texture called?

whitening — That which is used to render white; whiting. [R.] Whitening stone, a sharpening and polishing stone used by cutlers; also, a finishing grindstone of fine texture. (Webster's 1913.)