HC series has medium to high crystallinity and excellent high temperature and oxidation resistance. Microscopically, HC is a small agglomerate of smaller crystals with an overall medium specific surface area. The free Boron Oxide of HC and HC8 is typically higher than for other grades.

HC series is suitable as functional filler, lubricating additive, mold release agent for casting and injection molding because of its small size, larger aggregated particle size, three dimensional shape and more isotropic. Since HC and HC8 are not completely crystallize they are leaving enough room for further crystal growth and due to free Boron Oxide and Oxygen residues in the microstructure. they are suitable raw materials for hot-pressed ceramics. The HC-W grade has a lower boron oxide content and is the choice for use in industries with strictly limited Boron Oxide content.