
Armenian bole, also known as bolus armenus or bole armoniac, is an earthy
clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...
, usually red, native to
Armenia
Armenia, officially the Republic of Armenia, is a landlocked country in the Armenian Highlands of West Asia. It is a part of the Caucasus region and is bordered by Turkey to the west, Georgia (country), Georgia to the north and Azerbaijan to ...
but also found in other places. The term Armenian was later referred to a specific quality of the clay. Originally used in medication, it has also been used as a pigment, as a poliment or base for gilding, and for other uses.
It is red due to the presence of
iron oxide
An iron oxide is a chemical compound composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the best known of which is rust.
Iron ...
; the clay also contains hydrous
silicate
A silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is also used ...
s of
aluminum
Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
and possibly
magnesium
Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...
.
Uses
Historically, the term bolu or bolus was used only for medicinal earths and Armenian bole was used as an
astringent
An astringent (sometimes called adstringent) is a chemical that shrinks or constricts body tissues. The word derives from the Latin '' adstringere'', which means "to bind fast". Astringency, the dry, puckering or numbing mouthfeel caused by t ...
, prescribed against
diarrhea
Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...
,
dysentery
Dysentery ( , ), historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications may include dehyd ...
, and
bleeding
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethr ...
. References to Armenian bole were made by
Theophrastus
Theophrastus (; ; c. 371 – c. 287 BC) was an ancient Greek Philosophy, philosopher and Natural history, naturalist. A native of Eresos in Lesbos, he was Aristotle's close colleague and successor as head of the Lyceum (classical), Lyceum, the ...
,
Dioscorides
Pedanius Dioscorides (, ; 40–90 AD), "the father of pharmacognosy", was a Greek physician, pharmacologist, botanist, and author of (in the original , , both meaning "On Materia medica, Medical Material") , a 5-volume Greek encyclopedic phar ...
(c. 41–90 AD) and
Pliny the Elder
Gaius Plinius Secundus (AD 23/24 79), known in English as Pliny the Elder ( ), was a Roman Empire, Roman author, Natural history, naturalist, and naval and army commander of the early Roman Empire, and a friend of the Roman emperor, emperor Vesp ...
(23–79 AD). Externally, it was used in strengthening plasters, against dislocations of the joints. Physicians sometimes also called it ''Rubrica Synopica'', from the city of
Synope, where it is supposed to be found. Use for internal medicine may have side effects as the minerals often include heavy metals such as arsenic, cadmium, lead and zinc that can cause toxicity.
In the nineteenth century, it was incorporated into non-soluble
tooth powder. These types of powders would get stuck between the gums and the teeth and leave an unsightly discoloration. As a result, they were coloured red using Armenian bole to disguise the buildup around the teeth.
It is also used in
bookbinding
Bookbinding is the process of building a book, usually in codex format, from an ordered stack of paper sheets with one's hands and tools, or in modern publishing, by a series of automated processes. Firstly, one binds the sheets of papers alon ...
for coloring, or applied to the edges during
gilding
Gilding is a decorative technique for applying a very thin coating of gold over solid surfaces such as metal (most common), wood, porcelain, or stone. A gilded object is also described as "gilt". Where metal is gilded, the metal below was tradi ...
, as a base for the gold leaf and to give the binding a greater depth and luster.
In pottery, it is used as a red pigment for the
İznik pottery
Iznik pottery, or Iznik ware, named after the town of İznik in Anatolia where it was made, is a decorated ceramic that was produced from the last quarter of the 15th century until the end of the 17th century. Turkish stylization is a reflectio ...
of Turkey. Finally, it has also been used in the waterproofing of
windmill
A windmill is a machine operated by the force of wind acting on vanes or sails to mill grain (gristmills), pump water, generate electricity, or drive other machinery.
Windmills were used throughout the high medieval and early modern period ...
sails. A popular mixture was: 10 liters of water, combined with 0.75 liter linseed oil, 0.75 liter grease, and 1 kg of bolus.
Bolus used for windmill sail
/ref>
See also
* Levant bole, a similar clay, often used in place of Armenian bole
References
{{reflist
Natural materials
Medicinal clay