Hectorite is a rare soft, greasy, white clay mineral with a chemical formula of . Hectorite was first described in 1941 and named for an occurrence in the United States near Hector (in

San Bernardino County, California San Bernardino County (), officially the County of San Bernardino, is a county located in the southern portion of the U.S. state of California, and is located within the Inland Empire area. As of the 2020 U.S. Census, the population was 2,181, ...

, 30 miles east of Barstow.) Hectorite occurs with

bentonite Bentonite () is an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-m ...

as an alteration product of

clinoptilolite Clinoptilolite is a natural zeolite composed of a microporous arrangement of silica and alumina tetrahedra. It has the complex formula . It forms as white, green to reddish tabular monoclinic tectosilicate crystals with a Mohs hardness of 3.5 to ...

from

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer ...

and

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock ...

with a high glass content. Hectorite is also found in the beige/brown clay ghassoul, mined in the Atlas Mountains in

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria t ...

. A large deposit of hectorite is also found at the

Thacker Pass lithium deposit The Thacker Pass Lithium Mine is a proposed lithium clay mining development project in Humboldt County, Nevada which is the largest known lithium deposit in the US, and one of the largest in the world. There has been significant exploration of T ...

, located within the

McDermitt Caldera The McDermitt Caldera is a large, oval-shaped caldera west of McDermitt in southeastern Oregon and northern Nevada in the United States. It is about long north–south and wide east–west. The western part of the caldera is in the Trout Cre ...

in Nevada. The Thacker Pass lithium deposit could be a significant source of

lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid ...

. Despite its rarity, it is economically viable as the Hector mine sits over a large deposit of the mineral. Hectorite is mostly used in making cosmetics, but has uses in chemical and other industrial applications, and is a mineral source for refined lithium metal.

References

{{silicate-mineral-stub Smectite group Monoclinic minerals Minerals in space group 12 Lithium minerals Magnesium minerals Sodium minerals Minerals described in 1941

See also

References