Dickite (Al2Si2O5(OH)4) is a phyllosilicate clay mineral named after the metallurgical chemist Allan Brugh Dick, who first described it.

Dickite is an important alteration indicator[clarification needed] in hydrothermal systems as well as occurring in soils and shales.

Dickite's type location is in Pant-y-Gaseg, Amlwch, Isle of Anglesey, Wales, United Kingdom, where it was first described in 1888.

[12] In 1888, Allan Brugh Dick (1833–1926), a Scottish metallurgical chemist, was on the island of Anglesey to conduct research on kaolin.

The only way to determine the true identity of the mineral is through powder x-ray diffraction and optical means.

Another occurrence spot, as indicated by Brindley and Porter of the American Mineralogists journal, is the Northerly dickite-bearing zone in Jamaica.

Dickite is found worldwide in locations such as Ouray, Colorado, US; San Juanito, Chihuahua, Mexico, in a silicified zone among the rhyolite area; and in St. George, Utah, US, where the mineral is thought to be associated with volcanic rock.

It was found that groundwaters substantially heated along with magmatic waters which made its way up-dip and through the intrusions in the conduit-like algal mounds which allowed the dickite to be deposited in this area and it might be conclusive to say that this trend follows elsewhere in other locations around the world.

[9] Dickite takes on the appearance of a white, brown earthy color and is often found embedded in many other minerals such as quartz.

In a comparison of the family of minerals through experiments examined by Ross and Kerr the similarities between them are clearly evident and can, depending on the samples, be indistinguishable by optical means.

[5] The hexagonal structure and the stacking of the atoms influence the physical properties in many ways including the color, hardness, cleavage, density, and luster.

[10] Dickite's structure is made up of a shared layer of corner-sharing tetrahedra filled by a plane of oxygens and hydroxyls along with a sheet of edge-sharing octahedra with every third site left empty.

[10] X-ray experiments were performed by C. J. Ksanda and Tom F. W. Barth and it was concluded that dickite is composed of tiny layers of cations and anions which are parallel to the a-b plane stacked on top of one another which they found to be exactly as Gruner had described.