Refractory bricks, blocks, tiles and similar refractory ceramic constructional goods containing, by weight, >= 93% silica (excl. those of siliceous fossil meals or similar siliceous earths)
Opeka, bloki, ognjevarni, za vgraditev, nad 50% aluminijevega oksida (glinice), s 93% ali več silicijevega dioksida (SiO2) po masi