Origins of Ghassool

Where does Ghassool come from?

10/20/20232 min read

In the north african kingdom of Morocco you will find a unique clay said to be “saponiferic” that has been used for centuries and probably since the beginning of the highest Antiquity (XII and XIII centuries) by all the North African populations and in certain regions of the Middle-East. This clay is also known as Ghassoul or Rassoul; this term originates from the term “Rassala”, which means “to wash” in Arabic.

Geographical Origin

Ghassool that is currently commercialized in Morocco comes from the only deposits known in the world, located on the border of the mid Atlas, in the Moulouya valley, approximately 150-200 Km away from Fes. This exploitation is very ancient and takes place in underground mine galleries.

Geological Origin

Ghassool has a sedimentary formation of tertiary age and originates from lakes. Although the first chemical analysis was initiated by Damour in 1843, it is only in 1923 that Barthoux described the deposit, followed by Jeannette. Barthoux attributes this deposit to the Jurassic and situates this clay in a complex marly with gypsum that have irregular benches of limestone. The origin of this clay had been thoroughly discussed: for Yavamovitch (1936), Frey et Al (1936), Yvamovitch et Frey (1937), this clay comes from the hydration of material volcanic liquid; for Lapparent (1936-1937), it comes from the alteration of unstable volcanic rocks. It was only in 1977 that N. Trauth noticed the existence of a link between Ghassool and other clay rocks of a different mineralogical composition, which allowed him to explain the link between the genesis of the claylike minerals in Ghassool by a progressive transformation of the preexisting minerals in an environment rich in magnesium and silicon.

Ghassool Treatment

Once the Ghassoul is extracted from the underground galleries, it is treated and washed with water to eliminate the impurities. It is then spread out on large smooth surfaces and sun-dried. You consequently obtain a purified product in the form of plates and commercialized in Morocco.