By the nature of Genesis
In general you can divide glass into two groups: natural glass and artificial glass. While artificial glass is produced by the melting of several raw materials, natural glass is produced by processes in nature. The best known of such processes has to be the formation of obsidian and pumice. These natural types of glass result from volcanic eruptions of lava. Even a few millennia ago such natural glass was being used by humans for various purposes. Other natural glasses include tektites (meteorite impact) and fulgurites (lightning impact).
By the nature of „chemistry“
In modern times the majority of the glasses produced are known as soda-lime glasses (more). Due to the main component silicon dioxide (SiO2) these glasses are referred to also as silicate glass. Generally, in terms of quantity, the second most abundant oxide content in the silicate base glass is responsible for the classification into different groups. If the silicate glass has no other ingredients, i.e. made out of pure silica, it is referred to as silica or quartz glass. This very special glass is characterized by high thermal stability and chemical resistance. The low thermal expansion coefficient is also another plus of this type of glass. Phosphate or borate glasses, on the other hand, are characterized by a high content of phosphorus or boron trioxide. There are of course many more types of glasses, but we will not go into them in detail here.
By the basic shape of the product and the production processes
You can usually divide the glass industry into several key areas. Flat glass, hollow glass, utility and speciality glass industry, crystal and production glass industry, and the mineral fibre industry. Such a division, however, does not cover all aspects of the glass industry but is only a rough distinction between the different production technologies used in a nutshell. We want to briefly clarify these areas.
1) Flat glass is also called float glass depending on the production process. Flat glass can also be rolled or cast. Primarily, this type of glass concerns glass plates which are used as end products in construction and architecture, car glazing, solar glass, mirrors, display glass for screens of televisions, computers or smartphones, etc.
2) Hollow glass is found mainly in the food processing industry. Whether as a simple water bottle/jar, or whether involving other various types of glass packaging for the food industry, pharmaceutical manufacturers or the cosmetics industry – all of these areas are covered by the hollow glass industry. The very delicate process of making glass for light bulbs also falls under the scope of this industry.
3) Utility and speciality glass is as the name suggests, very specially manufactured glass. Among the main buyers include companies in the fields of precision mechanics and optics equipment, capital goods manufacturers, the electrical industry, engineering, communications and environmental engineering, medicine, science and chemistry
4) Crystal and production glass industry finds itself mainly useful for suppliers of drinking glasses and other glassware for the table and kitchen use
5) Mineral fibre industry is used in the production of insulation materials for construction (glass and stone wool), reinforcement fibre for the plastics industry as well as textile fibres (for example, yarn) for the textile industry.
Differentiation by trade name, brand name or generic term
Even here there are terms and names that have developed with time becoming a fixed constituent in our vocabulary. With the notion ‚ceramic‘ one thinks usually of the cooking surface in the kitchen. The household also often contains heat-resistant glass (borosilicate glass) for casserole dishes, glass lids of pots and pans, etc. There then is also the question of some very familiar brand names. There are other terms such as antique glass, optical glass, flint glass, crown glass, lava glass etc.
By intended use
Optical glasses for the production of prisms, lenses, optical components for binoculars, microscopes, object lenses are usually borosilicate glass, quartz, flint or crown glass. The generic term for technical laboratory glass is equipment glass (more). Another term for processed glass in the area of architecture and civil engineering is constructions glass. In astronomy and space, on the other hand, a very special glass ceramic material is used which is characterized by an extremely low coefficient of expansion.