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Mosaic gold

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(Redirected from Bronze powder) Inorganic pigment used for gilding
The Angel of Life by Giovanni Segantini. This work uses bronze powder, along with other media on paper.

Mosaic gold or bronze powder refers to tin(IV) sulfide as used as a pigment in bronzing and gilding wood and metal work. It is obtained as a yellow scaly crystalline powder. The alchemists referred to it as aurum musivum, or aurum mosaicum. The term mosaic gold has also been used to refer to ormolu and to cut shapes of gold leaf, some darkened for contrast, arranged as a mosaic. The term bronze powder may also refer to powdered bronze alloy.

A recipe for mosaic gold is already provided in the 3th century A.D. treatise Baopuzi, composed by the Chinese alchemist Ge Hong. 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's Libro dell'arte from the 1420s. Instructions became more widespread and varied thereafter, the around 1500 recipe collection Liber illuministarum from Tegernsee Abbey in Bavaria alone offering six different methods for its preparation. Alchemists prepared it by combining mercury, tin, sal ammoniac, and sublimated sulfur (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 convulsions of children; however, it is no longer recommended for any medical uses.

See also

References

  1. Holleman, A. F.; Wiberg, E. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN 0-12-352651-5.
  2. "Mosaic". Webster's Revised Unabridged Dictionary (1913). The ARTFL Project. p. 946. Retrieved 5 February 2014.
  3. "Ormolu". Webster's Revised Unabridged Dictionary (1913). The ARTFL Project. p. 1013. Retrieved 5 February 2014.
  4. Public Domain Chambers, Ephraim, ed. (1728). "Gold". Cyclopædia, or an Universal Dictionary of Arts and Sciences (1st ed.). James and John Knapton, et al.
  5. Butler, A. R.; Glidewell, Ch.; Needham, J.; Pritchard, S. (1983). Mosaic Gold in Europe and China, in: Chemistry in Britain 19/2 (1983), pp. 132–135.
  6. Section 172 in most editions of Cennini.
  7. Thompson, Daniel V. (2012-05-11). The Materials and Techniques of Medieval Painting. Courier Corporation. ISBN 978-0-486-14203-6.
  8. 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.
  9. "Aurum Mosaicum". Cyclopædia, or, an universal dictionary of arts and sciences - Full View - UWDC - UW-Madison Libraries. Cyclopædia, or, An universal dictionary of arts and sciences. 1728. AURUM Mosaicum is also a Preparation in Pharmacy, thus called from its golden Colour and Appearance. It is made of Mercury, Tin, Sal Armoniac, and Flowers of Sulphur, by grinding, mixing, then setting them three Hours in a Sand Heat.—The dirty Sublimate being taken off, the Aurum Mosaicum is found at the Bottom of the Mattrass. It is recommended in most chronical and nervous Cases; and particularly Convulsions of Children. Public Domain This article incorporates text from a publication now in the public domain: Chambers, Ephraim, ed. (1728). "Mosaic gold". Cyclopædia, or an Universal Dictionary of Arts and Sciences (1st ed.). James and John Knapton, et al.
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