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This heading covers all types of cast glass and rolled glass provided it is in sheets (whatever the thickness and whether or not cut to shape), or profiles, whether or not having an absorbent, reflecting or non-reflecting layer, but not otherwise worked.
It includes :(A) Unworked plate glass. This is generally non-transparent on account of its grained or rough surfaces. It may also be artificially coloured in the mass by means of metallic oxides or other salts. Surface ground or polished plate glass is excluded (heading 70.05). (B) A category of non-transparent glass which is more or less opacified in the mass and sometimes completely opaque. It is often made to resemble marble, porcelain (china) or alabaster in appearance. This type of glass is made in white, black and other colours, plain or veined, and is used for facing walls, for the manufacture of tops for washstands, counters, desks, tables, operating tables, etc., of tablets for gravestones, of advertising boards, signs, etc.
This type of glass may be intended for subsequent mechanical polishing on one or both faces, but when so treated it is excluded (heading 70.05). In the unworked state this glass shows marks resulting from contact with the roller or may bear traces of sand resulting from the casting. Certain opal glass has also one ribbed or rough surface in order to facilitate fixing. (C) A range of non-transparent glass, with an irregular surface obtained during manufacture. This group includes rough cast glass, cathedral glass, hammered cathedral glass, etc.; figured-rolled glass having one surface impressed with patterns (stripes, diamond patterns, ridges, etc.); corrugated glass and cast so-called antique glass (i.e., glass containing air bubbles, or crackled on the surface, or with other deliberate "defects"). Glass of these types, which may also be coloured in the mass, is used for the windows of factories, warehouses, offices, bathrooms and, in general, all premises where light is required but with varying degrees of obscuration.
Owing to the nature of the processes by which they are made, the types of glass in this category are not rendered plane by further processing. As already stated, this heading covers only cast glass and rolled glass.
In the casting process (which is being replaced, except in the case of large surfaces, by the rolling method), the molten glass is poured on to a fixed table. There are two metal flanges along the sides of the table to determine its thickness. The crucible is emptied in front of a heavy metal roller which runs on the flanges and squeezes the viscous mass of glass to the thickness of the flanges. As soon as the glass reaches the required consistency, it is passed slowly through an annealing tunnel or lehr, where the temperature gradually decreases towards the outlet, which is quite cool. During the casting process, profiles (e.g., U-shaped) can also be obtained by bending a glass ribbon lengthwise while still in a semi-molten state.
In the rolling process, the molten glass is passed between rollers from which it emerges either as a continuous ribbon or in sheets or profiles. It is then carried mechanically into a lehr.
It is during the casting or rolling processes that the surfaces of figured, hammered, etc., glass are impressed. In the casting method, either engraved casting tables or an engraved roller form the patterns in the semi-molten glass. In the rolling method, the desired effects are obtained by means of the final roller, which is engraved.
The types of glass described above may have holes obtained during manufacture, or may be wired. Plate, figured, cathedral and similar types of glass are sometimes wired where protection against the danger of splinters on disintegration or breakage is required, thus making it suitable for building purposes. Wired glass is almost always obtained by embedding a network of steel wire in the soft glass while it is being rolled.
Glass classified in this heading may have been flashed, generally with glass of another colour, during the manufacturing process or may have been coated with an absorbent, reflecting or non-reflecting layer, but not further worked.
The heading excludes not only cast glass and rolled glass which, by reason of subsequent processing, fall in other headings (e.g., heading 70.05, 70.06, 70.08 or 70.09), but also safety glass (heading 70.07) which may have been subject to rolling during manufacture.
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clhs@clhs.co.kr 
070-4214-8300