Abrasive powder made of silicon carbide, used in lithogragraphy to grind stones and in intaglio for the technique called carborundum.
Three grit sizes are available:
Coarse - 80
Medium - 150
Fine - 220
Available in 500g and 1kg jars.
The carborundum technique is not really an intaglio technique because the plate is charged with material instead of engraved. A grain is applied on the plate with a varnish or a binder. The plate should be sufficiently solid to receive the pressure of the press and to allow the cleaning after the print but is not necessarily a metal plate (plastic, certain cardboards, etc. can do the job).