feldsparryhmä

Feldsparryhmä refers to a group of rock-forming silicate minerals that are essential components of igneous, metamorphic, and sedimentary rocks. Feldspars are the most abundant mineral group in the Earth's crust, making up about 60% of all rocks. They are characterized by their chemical composition, which involves aluminum, silicon, and oxygen, along with alkali metals like potassium and sodium, or alkaline earth metals like calcium.

The feldspar group is broadly divided into two main series: the alkali feldspars and the plagioclase feldspars. Alkali feldspars include minerals like orthoclase, microcline, and sanidine, which are rich in potassium. Plagioclase feldspars are a solid solution series ranging from albite (sodium-rich) to anorthite (calcium-rich). The specific composition within the plagioclase series determines its properties and name.

Feldspars typically form in interlocking crystals and are often white, pink, or gray in color, though variations exist. They are relatively hard, with a Mohs hardness of 6, and possess two directions of cleavage at nearly right angles. Their presence and composition are crucial indicators for geologists in identifying rock types and understanding the geological history of an area. Feldspars are also important in industrial applications, such as in the ceramics, glass, and filler industries, due to their chemical stability and properties.