The stone, concrete, ceramics, and glass industries comprise the broader manufacturing and construction industries. Companies in the stone business take rock from the earth and manufacture it into either cut stone or partly finished stone. The products made from stone are grouped into nearly 20 different categories, including cut stone altars, baptismal fonts, benches, monuments, paving blocks, pulpits, tombstones, urns, and vases, as well as slate blackboards, burial vaults, curbing, marble pedestals and statues, slate roofing, and marble table tops.
Stone is a durable, adaptable material for building purposes, although a drawback is that it is more difficult to cut and transport than alternative materials. Today it remains popular, particularly as a material for enhancing the appearance of important structures, such as hotels, public buildings, and churches. In modern construction, a covering of stone veneer about two inches thick is applied in various patterns to exterior surfaces of buildings; the veneer is anchored and supported on a steel frame.
Concrete products are even more numerous than stone. This group also includes things made of gypsum, a material used in making plaster of paris and is thus useful for coating walls and ceilings. Some factories make only concrete blocks and bricks, which are used by builders. Others make more specialized items, such as bathtubs, burial vaults, ceiling squares, door frames, fireplaces, water fountains, incinerators, irrigation pipes, storage tanks, and septic tanks. Some companies produce ready-mixed concrete, orthopedic plaster, and wallboard.
The ceramics and glass industries use similar raw materials and the same basic technology to create adaptable, long-lasting products. Making both ceramic and glass products involves heat; for glass, the materials are usually heated first and then formed, whereas for ceramics, the materials are usually formed first and then heated. Ceramics and glass companies manufacture flat glass and other glass products, structural clay products, pottery, and other products from materials taken mainly from the earth in the form of clay and sand.
The glass and ceramics manufacturing industries are highly diversified and have direct impact on other industries, such as space technology, telecommunications, food chemistry, medicine, nuclear technology, and computer technology. One glass manufacturer alone has developed more than 65,000 different varieties of glass.
The glass industry is categorized into companies that make products within the following main divisions: flat glass, glass containers, pressed and blown glass and glassware, and glass products made of purchased glass. Flat glass companies produce glass used in buildings, cathedrals, insulation, windows, structures, and opticals. These companies treat raw glass with special coating, such as tempered and laminated glass. Tempered glass is heat-treated for strength and resistance; when it breaks, the edges are not jagged and thus are safer than non-tempered glass, which is why it's used for shower stalls, storefront doors, and fireplace screens. Laminated glass improves sound control, security, solar energy control, glare reduction, and resistance to windblown debris.
There are companies that make glass containers for commercial packing and bottling and for home canning, including medicine bottles, vials, water bottles, food jars, and wine and beer bottles. They make either narrow-neck or wide-mouth containers. Pressed and blown glass companies makes products ranging from tableware and Christmas tree ornaments to TV tubes and fiber optic cable, with some companies specializing in textile glass fibers and pressed lenses for vehicle lights, beacons, and lanterns.
Secondary glass manufacturing firms make products from glass purchased from other companies, such as shower doors, picture glass, clock glass, and oven door panels. These items are also used in many industrial, technical, and other non-household applications, such as bulletproof glass and gravity-sensing electrolytic transducers. Some of the more common glass products in this category, which represent various manufacturing methods, include lab glass, mirror glass, ornamental glass, safety glass, and stained glass. Other companies are more on the cutting edge of technology, producing items like glass wool insulation products, insulated fiber optic cable, and fiber optic medical devices.
The ceramics industry consists of companies that manufacture different kinds of ceramic products. This includes companies that make brick and structural clay tile, ceramic wall and floor tile, clay refractories, structural clay products, china plumbing fixtures, earthenware table and kitchen articles, porcelain electrical supplies, pottery products, and mineral wool.
Products made in the brick and structural tile group are used mainly for their structural properties rather than decorative purposes. They are used for building and paving. On the other hand, ceramic wall and floor tile is mainly decorative and is made for its aesthetic quality.
Refractories are products, such as brick, that are resistant to intense heat, making them ideal for walls, ceilings, blast furnaces, cement kilns, and open hearth furnaces. They are mainly used in fire-resistant construction materials for industrial buildings. Sewer pipe is a common structural clay refractory product. Other refractories are roofing tile, stove and flue lining, and architectural terra cotta.
Some companies make plumbing fixtures such as drinking fountains, urinals, flush tanks, and sinks; faucet handles and towel bar holders; china tableware and cookware; and commercial and household earthenware for cooking and serving food. Earthenware is porous, coarse, and opaque, unlike porcelain and bone china; these are all made with clay but earthenware is fired at lower temperatures and is more breakable than porcelain and china.
Unlike other ceramic sectors, the porcelain electrical supplies group involves high technology. These products, such as porcelain electronics insulators and spark plug porcelain, are good insulators for electricity because of how they channel heat. Low-tech companies, on the other hand, make art and ornamental pottery and industrial and lab pottery, and some fire and decorate white china and earthenware. In this group, manual labor is more common than automation, and a lot of the machinery used has not changed much in the last 50 years.
The last group, mineral wool, produces two main products: mineral wool for thermal and acoustical insulation and mineral wool for industrial, equipment, and appliance insulation. Products made in this group include acoustical board and tile, fiberglass insulation, glass wool, and roofing mats.
Other branches of the glass and ceramics industry involve non-manufacturing elements. In addition to production, companies also are involved in research, development, and distribution. Many companies are in the business of supplying raw materials to the industrial ceramics and glass industries, including such materials as clay, silica, alumina, feldspar, metallic oxides, special glasses for enamels, ferrites for ceramic magnets, and a multitude of other materials for various special applications. Today, it is essential that suppliers be knowledgeable about the materials they sell. Many suppliers hire engineers who oversee the development of their materials and products. The raw materials industry is highly competitive, demanding close control over material composition and properties. The material supplier must always be ready and willing to assist the customer with technical problems.
Raw materials are usually sold to suit specific products. An engineer develops a new concept and tells the developers and researchers what is required on the production line, what new products a customer needs, and what current problems the customer or industry is encountering. At this stage, developers and researchers begin the creation of new products. The researcher then examines the raw materials with sophisticated types of analytical equipment, such as electron microscopes, mass spectrometers, X-ray diffractors, many types of spectrographs, differential thermal analysis devices, thermogravimetric analysis equipment, and sophisticated high-temperature furnaces. Next, development engineers work with production personnel to produce finished articles. Production workers use processing and operating equipment such as grinders, milling machines, sieves, mixing equipment, presses, and spray driers to aid in this process. When a product is completed, salespeople create or expand the market for the item and sell it to clients. The salesperson is active in the development aspect, providing consumer feedback and other marketing information.