Hedenbergite: The mineral Hedenbergite information and pictures

About

Hedenbergite forms a series with Diopside, the magnesium equivalent of Hedenbergite, and may be partially replaced by it. Diopside and Hedenbergite can even occur together in a single crystal, with a core of Hedenbergite and outer zone of Diopside. Hedenbergite is often confused and misidentified as both Diopside and Augite.

Crystal Forms & Aggregates

Crystals are stubby and prismatic, and usually have a rectangular cross section. Elongated crystals are uncommon. Also occurs grainy, columnar, acicular, massive, radiating, and fibrous. May also be in v-shaped penetration twins, and crystals from certain localities have partially hollow etchings.

Striking Features

Color, cleavage angles, and mineral associations

Environment

Contact metamorphic rocks in hornfels, and in skarn deposits of hydrothermal metamorphic rock.

Uses

Large Hedenbergite crystals are uncommon and of interest to mineral collectors.

Noteworthy Localities

This mineral is more common than perceived, and is often misidentified as Diopside or Augite. Fibrous and radiating aggregates occur in Italy at Temperino, Campiglia Marittima, in Livorno Province. Dark, lustrous crystals come from Nordmark, Varmland, Sweden; and famous green Quartz with Hedenbergite inclusions in Quartz from Mega Xhorio, Seriphos Island, Greece.

Another locality with excellent Hedenbergite inclusions in Quartz is the Sinerechenskoye deposit, west of Kavalerovo, Primorskij Kraj, Russia, where the Quartz is darker green and forms pointier crystals than the Greek locality. Dal'negorsk, in Primorskij Kraj, Russia has several important deposits containing Hedenbergite. Good crystals, sometimes translucent, come from Broken Hill, New South Wales, Australia; and dark lustrous crystals from Tormiq, Haramosh Mountains, Pakistan.

In the U.S., good Hedenbergite crystals come from Franklin, Sussex Co., New Jersey; Warwick, Orange Co., New York; Keene, Essex County, New York; and the Iron Cap Mine, Graham County, Arizona. Aesthetic prismatic crystal groupings of Hedenbergite come from the Laxey Mine, South Mountain, Owyhee Co., Idaho.

Common Mineral Associations

Quartz, Grossular, Andradite, Vesuvianite, Calcite, Wollastonite, Actinolite, Ilvaite, Magnetite

Distinguishing Similar Minerals

Epidote - Different cleavage, usually heavily striated.
Enstatite and Augite - Very difficult to distinguish.
Diopside - Usually lighter in color, otherwise cannot be distinguished practically.