Wollastonite
Calcite is, however, by quantity the main economic mineral (55–75%) in this ore type. This formation of wollastonite seems to be older than the rapakivi magmatism (∼1600 Ma), because rapakivi dikes clearly crosscut this silicate banding, and an age determination from the titanite fraction from this type yielded 1858 ± 20 Ma (unpublished data, determination by H. Huhma; Lehtinen, 1995).