Richterite is a sodium calcium magnesium silicate mineral belonging to the amphibole group.

Colors of richterite range from brown, grayish-brown, yellow, brownish- to rose-red, or pale to dark green.

Richterite occurs in thermally metamorphosed limestones in contact metamorphic zones.

It also occurs as a hydrothermal product in mafic igneous rocks, and in manganese-rich ore deposits.

The mineral was named in 1865 for the German mineralogist Hieronymous Theodor Richter (1824–1898).