Litchfieldite

[2] Litchfieldite is composed of two varieties of feldspar (mostly albite but also some microcline), with nepheline, sodalite, cancrinite and calcite.

The mafic minerals, when present, are magnetite and an iron-rich variety of biotite (lepidomelane).

[3][4] It is a very rare rock and also occurs in Blue Mountain and French River, Canada;[4] Soroy and Val River, Norway; Cevadais, Portugal; Canaã,[5] Boca Nova, Itajú da Colonia and Peixes, Brazil.

Besides the mineral composition litchfieldites are characterized by one or more of the following structures: There are two hypotheses for the origin of these rocks: Both schools of thought are in accordance that rocks like litchfieldite owe their mineral and structural characteristics to the metamorphism.

Due to the content of alkali elements and alumina, they are very important ore for the glass industry.