The glass industry is one of the primary consuming markets for IM, with the highest demand in terms of volume for silica sand, limestone, feldspar and soda ash. The specifications of the mineral are crucial to the properties of the glass, notably its colour, brightness and resistance.
The two main categories of glass are container glass (bottles, tableware, etc.) and flat glass (windows in buildings and cars). Speciality glass is produced in lower quantities but accounts for important technological uses, as well as in our everyday lives. The special characteristics of the finished products derive from the addition of minerals, often in low quantities (rare earths) or in more significant amounts (borates). The most common of such speciality glasses are borosilicates, commonly known as "Pyrex".
As technology improves, requirements for speciality glass are ever increasing and, to a significant extent, pace technological developments. Some of these applications are exponentially growing, as for example optic fibre cables in computer links, aerospace and other IT developments.
Others are already part of the technology of our everyday lives, for example TV screens. Fibreglass and glass wool are also members of this big family. The mineral blend is determinant to the glass properties during manufacture and use. The elongation properties of glass fibres is for example dependent upon the borate content of the melt batch.