… sands); quartzite, whether or not roughly trimmed or merely cut, by sawing or otherwise, into blocks or slabs of …
Explanatory notes
… sands); quartzite, whether or not roughly trimmed or merely cut, by sawing or otherwise, into blocks or slabs of … intended to be used for technical purposes, e.g., as piezo‑electric quartz or for the manufacture of parts of tools. … (b) Flint or other products of heading 25.17 . (c) Optical elements of quartz ( heading 90.01 ). …