Maasälpäryhmää

Maasälpäryhmää refers to a group of feldspar minerals. Feldspars are a group of rock-forming tectosilicate minerals that make up about 41% of the Earth's continental crust by weight. They are essential components of most igneous rocks and are also found in many metamorphic and sedimentary rocks. The term "maasälpäryhmää" translates directly from Finnish as "feldspar group."

The feldspar group is broadly divided into two main subgroups: alkali feldspars and plagioclase feldspars. Alkali feldspars, also known as potassium feldspars, are characterized by their potassium content, with orthoclase and microcline being common examples. Plagioclase feldspars are a solid solution series ranging from albite (sodium-rich) to anorthite (calcium-rich). The precise composition of plagioclase feldspars is indicated by their anorthite content.

These minerals are distinguished by their distinct physical properties, including hardness, cleavage, and specific gravity, which can vary slightly depending on their precise chemical composition. Feldspars are known for their two good cleavages, which intersect at approximately 90 degrees. They are generally harder than glass and typically appear white, pink, or gray, though they can also occur in other colors.

Feldspars play a significant role in geology. Their weathering contributes to the formation of clay minerals and sediments. In igneous rocks, the relative abundance and composition of feldspars are key indicators for classifying rock types. In industry, feldspar is used in the manufacturing of ceramics, glass, and as a filler in paints and plastics.