An earthy clay that is typically red and is native to Armenia but can also be found elsewhere is called Armenian bole, also known as bolus armenus or bole armoniac. Later, the term "Armenian" was used to describe a particular property of the clay. It was once employed as medicine, but it has since been put to use as a pigment, poliment, foundation for gilding, and for other things. The iron oxide that gives it its red colour is also present in the clay, which also has hydrous silicates of magnesium and potentially aluminium.

Historically, the term "bolu" or "bolus" was only applied to medicinal earths, and Armenian bole was astringent medicine used to treat bleeding, diarrhoea, and dysentery. Theophrastus, Dioscorides (c. 41-90 AD), and Pliny the Elder all mentioned Armenian bole (23–79 AD). It was applied externally to reinforce plasters to prevent joint dislocations. Because it is thought to be located in the city of Synope, doctors have sometimes referred to it as Rubrica Synopica. As the minerals frequently include poisonous heavy metals including arsenic, cadmium, lead, and zinc, use for internal medicine may have adverse effects.

It was added to non-soluble teeth powder in the nineteenth century. These powders would create an ugly stain by being lodged between the gums and the teeth. They were therefore painted crimson with Armenian bole to hide the accumulation around the teeth.

Moreover, it is used in bookbinding as a substrate for the gold leaf to add depth and lustre to the binding as well as for colouring or applying to the edges during gilding. It is utilised in ceramics as a red colour for Turkish znik pottery. In addition, it has been used to waterproof windmill sails. A common concoction was 10 litres of water, 0.75 litres of grease, 0.75 litres of linseed oil, and 1 kg of bolus.