Quartz is the naturally occurring crystal form of silica.
It falls in this heading only if complying with both of the following two conditions :(a) It must be in the crude state or have not undergone any process beyond that allowed in Note 1 to this Chapter; for this purpose, heat treatment designed solely to facilitate crushing is regarded as a process permitted by Chapter Note 1. (b) It must not be of a variety and quality suitable for the manufacture of gem‑stones (e.g., rock crystal and smoky quartz, amethyst and rose quartz). Such quartz is excluded (heading 71.03), even if intended to be used for technical purposes, e.g., as piezo‑electric quartz or for the manufacture of parts of tools. Quartziteis the name of very hard compact rock composed of grains of quartz agglomerated by a siliceous binder. Quartzite falls in this heading when in the crude state or when it has not undergone any process beyond that allowed by Note 1 to this Chapter or when it has been roughly trimmed or merely cut, by sawing or otherwise, into blocks or slabs of a rectangular (including square) shape. It is to be noted, however, that quartzite in shapes identifiable as road or paving setts, flagstones or curbstones is excluded (heading 68.01), even if merely shaped or processed as specified in the heading text. The heading also excludes : (a) Natural quartz sand (heading 25.05). (b) Flint or other products of heading 25.17. (c) Optical elements of quartz (heading 90.01).
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