Formula: CaFe2+Si2O6

Colour: Brownish green, black

Lustre: Vitreous, Dull

Hardness: 5½ – 6½

Specific Gravity: 3.56

Crystal System: Monoclinic

Member of: Clinopyroxene Subgroup > Pyroxene Group

Name: Named in 1819 by Jöns Jakob Berzelius in honor of Mr. Anders Ludvig (Ludwig) Hedenberg  (1781-1809), formerly a clerk associated with Mountain College, and later chemistry student and co-worker with Berzelius and who first found it at Mormorgruvan, Tunaberg, Sweden.

Type Locality: Mormorsgruvan, Tunaberg Cu-Co Ore Field, Tunaberg, Nyköping, Södermanland County – Sweden