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Stacked Witherite Aggregate
CARBONATES; ARAGONITE GROUP · ORTHORHOMBIC

Witherite

BaCO3

Hardness
3–3.5
Streak
White
Spec. Gravity
4.3–4.6
System
Orthorhombic

About

Witherite is an uncommon mineral, especially since it easily alters to the more common mineral Barite. It alters when sulfuric acid from sulfide minerals dissolves the Witherite, and the sulfur combines with the barium to form Barite. Witherite is also formed from Calcite that loses its calcium, and gets replaced by barium, thus forming Witherite in the process.

Witherite was named by Abraham Gottlob Werner in honor of William Withering (1741-1799), an English geologist, chemist, botanist, and physician. Withering is credited with the identification of this mineral as a separate species from Barite.

Crystal Forms & Aggregates

Crystals are always almost always twinned, usually in pseudohexagonal trillings that are bipyramidal, resembling bipyramidal hexagons. Crystals may also be elongated pseudohexagonal trillings that are not bipyramidal, and are usually scepter shaped. May also be in bladed or tabular crystals. Most crystals have striations on crystals faces, which sometimes may be deep indentations. Witherite also occurs fibrous, grainy, platy, mammilary, columnar, crusty, massive, and as groups of crystals in layers.

Other ID Marks

Complex Tests

Striking Features

Environment

Uses

Witherite is used in the production of glass. Good crystals of this mineral are highly desirable among collectors.

Noteworthy Localities

There are not many significant localities for Witherite. The two most noteworthy localities are are the deposits in Alston Moor, North Pennines, Cumbria, England; and the Minerva No. 1 Mine, Cave-in-Rock, Hardin Co., Illinois. Other occurrences are the Fallowfield and Settlingstones Mines, Acomb, near Hexham, Northumberland,  England; the Pigeon Roost Mine, Glenwood, Montgomery Co., Arkansas; El Portal, Mariposa Co., California; and Thunder Bay, Ontario, Canada.

Common Mineral Associations

Distinguishing Similar Minerals

Photos

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Crystal forms

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Hexagonal Biyramidal
Hexagonal with pyramidal prisms
Flat Tabular Hexagonal Disc
Tabular Non-Twinned Individual Crystal
Rounded Tabular