TYPES OR VARIETIES OF GLASS
1) WATER GLASS OR SOLUBLE GLASS
It is a thick syrupy liquid obtained by fusing SiO2 with Sodium Carbonate. It is used as an adhesive in paper manufacture, fire proofing and egg preservation.
2)SODA GLASS OR SOFT GLASS
This glass is a mixture of sodium and calcium silicate having the composition, Na2O. CaO. 6Si02. It is easily fused and is used in making glass tubes, plate glass and laboratory apparatus.
3) POTASH LIME GLASS OR HARD GLASS
This glass is a mixture of potassium and calcium silicates and is represented by the formula: K2O. CaO. 6Si02. The potash lime glass is very difficult to fuse hence is called hard glass. This glass is used in making hard glass apparatus.
4) POTASH LEAD GLASS OR FLINT GLASS
This glass is a mixture of potassium and lead silicates, having the composition, K2O. PbO. 6Si02. This glass has a brighter luster and greater refractive index value than any other variety of glass. Flint glass is used in the manufacture of artificial gems, lenses, prisms and electric bubbles.
(5) BOTTLE GLASS OR COMMON GLASS
This glass is a mixture of sodium, calcium and iron silicates and is represented by the formula: Na20. CaO. Fe203. Si02. It is obtained from cheap raw material and is yellow or brown in colour. This glass is used in making ordinary bottles.
(6) PYREX GLASS OR JENA GLASS
It is a special type of high class hard glass. This glass is a mixture of borosilicates and alumina-silicates of potassium and calcium. The pyrex glass has low co-efficient of expansion and is used for the preparation of scientific apparatus.