Giovanni_Segantini_-_The_Angel_of_Life_-_Google_Art_Project

Mosaic gold or bronze powder refers to tin(IV) sulfide as used as a pigment in bronzing and

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 ...

wood and metal work. It is obtained as a yellow scaly crystalline powder. The

alchemist Alchemy (from the Arabic word , ) is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practised in China, India, the Muslim world, and Europe. In its Western form, alchemy is first ...

s referred to it as aurum musivum, or aurum mosaicum. The term mosaic gold has also been used to refer to

ormolu Ormolu (; ) is the gilding technique of applying finely ground, high-carat gold– mercury amalgam to an object of bronze, and objects finished in this way. The mercury is driven off in a kiln, leaving behind a gold coating. The French refer to ...

and to cut shapes of

gold leaf upA gold nugget of 5 mm (0.2 in) in diameter (bottom) can be expanded through hammering into a gold foil of about 0.5 m2 (5.4 sq ft). The Japan.html" ;"title="Toi gold mine museum, Japan">Toi gold mine museum, Japan. Gold leaf is gold that has ...

, some darkened for contrast, arranged as a

mosaic A mosaic () is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/Mortar (masonry), mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and ...

. The term bronze powder may also refer to powdered

bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloid ...

alloy. A recipe for mosaic gold is already provided in the 3th century A.D. treatise ''

Baopuzi ''Baopuzi'' () is a literary work written by Ge Hong (AD 283–343), (), a scholar during the turbulent Jin dynasty. ''Baopuzi'' is divided into two main sections, the esoteric ''Neipian'' () and the section intended for the public to unders ...

'', composed by the Chinese alchemist

Ge Hong Ge Hong (; b. 283 – d. 343 or 364), courtesy name Zhichuan (稚川), was a Chinese linguist, philosopher, physician, politician, and writer during the Eastern Jin dynasty. He was the author of '' Essays on Chinese Characters'', the '' Baopu ...

. The earliest sources for its preparation in Europe, under the name ''porporina'' or ''purpurina'', are the late 13th-century North Italian '' Liber colorum secundum Magistrum Bernardum'' and

Cennino Cennini Cennino d'Andrea Cennini (; – before 1427) was an Italian painter influenced by Giotto. He was a student of Agnolo Gaddi in Florence. Gaddi trained under his father, called Taddeo Gaddi, who trained with Giotto. He is remembered mainly f ...

's ''Libro dell'arte'' from the 1420s. Instructions became more widespread and varied thereafter, the around 1500 recipe collection '' Liber illuministarum'' from

Tegernsee Abbey Tegernsee Abbey ( German ''Kloster Tegernsee'' or ''Abtei Tegernsee'') is a former Benedictine monastery in the town and district of Tegernsee in Bavaria. Both the abbey and the town that grew up around it are named after the Tegernsee, the lake ...

in Bavaria alone offering six different methods for its preparation.Recipes 26, 30, 1122, 1141, 1142, 1188 in: ''Liber illuministarum aus Kloster Tegernsee''. Bartl, A; Krekel, Ch.; et al. (edd., transl., comm.). Stuttgart 2005; rendered into modern chemical formulas pp. 536-538. Alchemists prepared it by combining mercury,

tin Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the ...

sal ammoniac Salammoniac, also sal ammoniac or salmiac, is a rare naturally occurring mineral composed of ammonium chloride, NH4Cl. It forms colorless, white, or yellow-brown crystals in the Cubic (crystal system), isometric-hexoctahedral class. It has very ...

, and sublimated

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

(fleur de soufre), grinding, mixing, then setting them for three hours in a sand heat. The dirty sublimate being taken off, aurum mosaicum was found at the bottom of the matrass. In the past it was used for medical purposes in most chronic and nervous ailments, and particularly

convulsion A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is often used as a synony ...

s of children;
/ref> however, it is no longer recommended for any medical uses.

References

{{reflist , 30em Inorganic pigments Visual arts materials Alchemical substances Tin(IV) compounds Powders Sulfides

See also

References