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Feldspar is a group of nine common minerals that are located in the Earth crust. The name was gotten from the German “Feld” and a rock that has no ore called “spath”. Resources containing feldspar are referred to as being “Feldspathic”.


The group actually contains 20 feldspars, but only nine of them are widespread. They are divided into two groups: the Plagioclase feldspars and the Alkali or K feldspars which are differentiated by composition and chemistry. The Plagioclase feldspars include a group of seven members, starting from a member, rich in the sodium element to the last member which is rich in potassium: the Albite, the Oligoclase, the Andesine, the Labradorite, the Bytownite, and the Anorthite.

On the other hand, the Alkali feldspars are polymorphs. This means that their chemical composition is similar but, they have different arrangements thus making them dissimilar minerals. The members include the Microcline, the Sanidine, and the Orthoclase.

Other types of feldspar are the not so common Barium feldspars which are monoclinic and include the Celsian and the Hyalophane.

What are the applications of Feldspar?

The feldspar is a raw substance which is widespread and is used to make ceramics and glass. It can also be used as filler in plastics, rubber and paint.

Feldspar is good for glassmaking because alumina in feldspar helps to make the glass hard, durable and resistant to compound decomposition. It is also effective in ceramics because the alkalis from feldspar (e.g. calcium oxide) operates as a flux and considerably reduces the melting point of the mixture. The flux melts early on during the process of firing, and this forms a flat mold that bonds the rest of the system components together.

In the United States, the amount of feldspar consumed in the production of glass is 66%. The remaining 34% is used for pottery, house flooring, wall sockets and fillers. Feldspar also has applications in archaeology and earth sciences.


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