2506 Quartz (excl. natural sands), quartzite, whether or not roughly trimmed or merely cut, by sawing or otherwise, into blocks or slabs of a square or rectangular shape

2506 (01/1988-..) Quartz (excl. natural sands), quartzite, whether or not roughly trimmed or merely cut, by sawing or otherwise, into blocks or slabs of a square or rectangular shape 25061000 (01/1988-..) Quartz (excl. quartz sands) 25062000 (01/2007-..) Quartzite, merely cut, by sawing or otherwise, in blocks or slabs of a square or rectangular shape 25062100 (01/1988-12/2006) Crude or roughly trimmed quartzite 25062900 (01/1988-12/2006) Quartzite, merely cut, by sawing or otherwise, in blocks or slabs of a square or rectangular shape (excl. roughly trimmed)