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Large Pearly Brucite
OXIDES; HYDROXIDES · HEXAGONAL

Brucite

Mg(OH)2

Hardness
2–2.5
Streak
White
Spec. Gravity
2.3–2.4
System
Hexagonal

About

Brucite is most often in crude, uninteresting form, but several localities produce distinct and interesting crystals which are highly desirable to collectors. Brucite may form as a standalone mineral, but it can also form as layers within minerals of the chlorite group and clay minerals such as Montmorillonite and Smectite. It forms a component of certain types of marbles, which are commercially known as pearl grey marble.
Brucite is named in honor of Archibald Bruce (1777-1818), a mineralogist who first described this mineral.

Crystal Forms & Aggregates

Other ID Marks

Striking Features

Sectility

Environment

Varieties

✓ common  · ✗ uncommon

Uses

Brucite is used as a source of magnesium, and is also mined for a Brucite marble. Large individual crystals ans well-formed crystal groups are rare and desirable collector's minerals, especially those from the defunct Wood's Chrome Mine in Pennsylvania.

Noteworthy Localities

Although Brucite is generally a common mineral, specimens worthy of collection only come from a handful of locations worldwide. In Italy, light blue crystal plates have come from the Val di Serra Quarry, Pilcante, Trento Province, Italy. The Kalahari manganese field, in Northern Cape Province, South Africa has produced exceptional examples of Brucite. This includes botryoidal aggregates and rounded, ball-like crystals of all colors at the N'Chwaning Mines at Kuruman; and blue and yellow Brucite in rounded crystal masses from the Wessels Mine, at Hotazel. A new find of bright yellow Brucite from the Killa Saifullah District, Balochistan, Pakistan, has recently popularized this mineral, with an abundance of exceptionally-colored rounded crystal groups that have redefined this mineral for collectors.
In the U.S., Brucite was first described from Castle Hill, Hoboken, Hudson Co., New Jersey, the type locality also known for the presence of its Nemalite variety. One of the most classic localities for this mineral is Wood's Chrome Mine, Texas, Lancaster Co., Pennsylvania, where some of the largest crystals of Brucite were found. Excellent crystals also come from the nearby Cedar Hill Quarry, Fulton Township, Lancaster Co., Pennsylvania. Good Brucite crystals are found at the Sierra Magnesite Mine, Gabbs, Nye Co., Nevada. In Canada, foliated crystal plates have come from the Maxwell quarry, Wakefield, Québec.

Common Mineral Associations

Distinguishing Similar Minerals

The characteristics of Brucite can usually distinguish it from other minerals. However, it can have similar properties to Gypsum, but the crystal habits are usually very different.

Photos

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Crystal forms

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Modified Trigonal
Hexagonal Tabular