This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
Mosaic gold, generally a compound of tin, 64.63 parts, and sulphur, 35.37 parts, is odorless and tasteless, and dissolves only in chlorine solution, aqua regia, and boiling potash lye. It is employed principally for bronzing plaster-of-Paris figures, copper, and brass, by mixing it with 6 parts of bone ashes, rubbing it on wet, or applying it with varnish or white of egg in the preparation of gold paper or for gilding cardboard and wood. Mosaic gold of golden-yellow color is produced by heating 6 parts of sulphur and 16 parts of tin amalgam with equal parts of mercury and 4 parts of sulphur; 8 parts of precipitate from stannic muriate (stannic acid) and 4 parts of sulphur also give a handsome mosaic gold.
The handsomest, purest, and most gold-like mosaic gold is obtained by melting 12 parts of pure tin, free from lead, and mixing with 6 parts of mercury to an amalgam. This is mixed with 7 parts of flowers of sulphur and 6 parts of sal ammoniac, whereupon the mass is subjected for several hours to a heat which at first does not attain redness, but eventually when no more fumes are generated is increased to dark-red heat. This operation is conducted either in a glass retort or in an earthenware crucible. The sal ammoniac escapes first on heating, next vermilion sublimates and some stannic chloride, while the mosaic gold remains on the bottom, the upper layer, consisting of lustrous, golden, delicately translucent leaflets, being the handsomest mosaic gold.
This is obtained by the finely ground waste from beating leaf silver or by dissolving silver in aqua fortis. This solution is then diluted with water and brightly scoured copper plates are put in, whereby the silver precipitates as a metallic powder.
This is obtained through the waste in beating imitation leaf silver, which, finely ground, is then washed and dried. In order to increase the luster it is ground again in a dry condition.
Mosaic silver is an amalgam of equal parts of mercury, bismuth, and tin. One may also melt 50 parts of good tin in a crucible, and as soon as it becomes liquid add 50 parts of bismuth, stirring all with an iron wire until the bismuth is fused as well. As soon as this occurs the crucible must be removed from the fire; then stir in, as long as the contents are still liquid, 25 parts of mercury and mix the whole mass evenly until it can be ground on a stone slab.