Fältspole

Fältspole is a variety of potassium-rich igneous rock found in Sweden, particularly in the skarns and gneisses. The name "fältspole" is derived from the Swedish words for "feldspar" and "schist", referring to its mineral composition and texture.

Chemically, fältspole is a type of alkali feldspar, a mineral group that also includes sanidine, orthoclase, and microcline. Its crystal structure consists of a framework of interconnected silicon and oxygen tetrahedra, with potassium ions occupying spaces within the framework. This characteristic of fältspole allows it to be a common component of granitic rocks.

Fältspole has several distinct characteristics that set it apart from other feldspar varieties. It typically has a fine-grained texture and a glassy appearance, which is a result of rapid cooling during its formation. Its prismatic crystals often exhibit irregular arrangements, giving fältspole a characteristic undulates pattern. Another notable feature is the presence of inclusions, such as quartz and other minerals, that are commonly incorporated into its crystal structure.

In terms of geographic distribution, fältspole can be found in several regions throughout Sweden, including the provinces of Bergslagen, Mora, and the Kane mountains. The rock is often associated with occurrences of orthogneisses, granite andsxenite. The economic significance of fältspole is relatively minor compared to other Swedish rocks of significance.