Alum stone

Potassium alum is manufactured by treating bauxite with sulfuric acid and then potassium sulfate. Alternatively, aluminum sulfate is reacted with potassium sulfate, or the mineral alum stone, alunite, can be calciaed and leached with sulfuric acid. Alunite is a basic potassium aluminum sulfate... 

Alaun-schiefer, m., -schiefererz, n. alum slate, alum shale. -seife, /. aluminous soap, -sieden, n. alum boiling, alum making, -sieder, m. alum boiler, -siederei, /. alum works, -stein, -spat, m. alum stone, alunite. alaunt, p.a. alumed. 

Berg-ader, /. lode, vein, -akademie, /. school of mines, -alaun, m. rock alum, roche alum (Roman alum) alum stone, alumte. beigan, adv. uphill. 

The best native source for this is the mineral Alunite (or Alum stone) which is ground and roasted, then dissolved in water. After filtration, the water is evaporated to obtain crystals of Alum. 

Although aluminum was one of the last metals to be commercialized, it has been recognized for centuries. Aluminum was first recognized by the Romans as an astringent substance, and they called it alum . By the Middle Ages it was manufactured as alum stone , a subsulfate of alumina and potash. In 1825, Hans C Oersted was able to isolate a few drops of the raw material, and then by 1886 it had patents from both Charles Martin Hall of the United States and Paul-Louis-Toussaint Heroult of France. Aluminum was commercialized in industry by the end of the nineteenth century. 

Father Athanasius Kircher said that the phosphorus was made by pulverizing the Bologna stone, mixing it with white of egg or linseed oil, and calcining it in a special furnace. He found specimens in the alum mines at Tolfa (59). Biographical sketches of Father Kircher were published in The Hormone in 1934. (109) and in the Journal of Chemical Education in 1955 (139). 

The substances used for cleaning and roughening the surface of the stone so as to facilitate the absorption or adherence of the color are various. Alum, which doubtless comprised as with Dioscorides and Pliny salts of iron as well as of aluminum, is frequently used, although white alum is here often specifically mentioned. Urine is frequently used, its efficiency being doubtless due to the carbonate of ammonium formed on standing. Limewater, sodium carbonate, vinegar, and a solution of sulphur and lime (polysulphides of calcium) are other constituents of the mordanting solutions. 

Another recipe for emerald says to take iridescent Indian crystal and form stones from it. This very probably refers to the same stone as the one above-mentioned, and tends to confirm the interpretation of von Lippman. In this recipe the stone when shaped (cut) is immersed for three days in a paste made from alum schist, human feces and vinegar. 

First of glacial alum. Many kinds can be used without any purification. Nevertheless it is purified in this manner. It is placed in an alembic and thus the whole humidity extracted which is of much value in this art. The residue (feces) remaining in the bottom of the vessel is either dissolved upon the stone in some moist place, or extracted with water, or reserved. ... 

Agricola divides the minerals into 1. earths, such as clays, chalks, ochres, etc. 2. stones, properly so called, gems, semiprecious stones. 3. solidified juices, (succi concreti), salt, alum, vitriols, saltpeter, etc. This is an application of the theory of the ancients that these are derived from solidified waters. 4. rocks, such as marble, serpentine, alabaster, limestone, etc., hard and not friable like the earths. 5. metals. 6. compounds, or mixtures, under which head he classes various ores of the metals, from which he recognizes that simpler constituents, as the metals, may be obtained. The fundamental basis of this classification Agricola explains in the following manner.80... 

Soda (nitrum) is also briefly described. Saltpeter, its origin and production from earth in which it has rested many years, and from exudations from stone walls of wine cellars and dark places is described much as by Biringuc-cio, from whose work it appears to have been somewhat condensed. Then follows the manufacture of alum, vitriol, sulphur, bitumen and finally of glass of which he gives a clear and interesting description concluding ... 

A powder which burns with a green flame is obtained by the addition of nitrate of baryta to chlorate of potash, nitrate of potash, acetate of copper. A white flame is made by the addition of sulfide of antimony, sulfide of arsenic, camphor. Red by the mixture of lampblack, coal, bone ash, mineral oxide of iron, nitrate of strontia, pumice stone, mica, oxide of cobalt. Blue with ivory, bismuth, alum, zinc, copper sulfate purified of its sea water [sic]. Yellow by amber, carbonate of soda, sulfate of soda, cinnabar. It is necessary in order to make the colors come out well to animate the combustion by adding chlorate of potash.15... 

Rocca stone, from which Alum is derived. 

AMIANTHUS, or AMIANTUS — On the testimony of Dioscorides, is a stone of Cyprus, not unlike certain species of alum. It is impervious to fire, from which it issues more brilliant. It is fabled by the Germans to be produced from the hairs of a Salamander, which is accounted for by its fireproof nature. It is a kind of stone which may be split into threads and spun. It is without doubt a... 

ASSOS — An artificial alum of the appearance of the stone, i.e., white. See Morien. 

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