The Collaborative International Dictionary
massicot \mas"si*cot\, n. [F. massicot; E. masticot is a corruption.] (Chem.) Lead monoxide (also called Lead protoxide), PbO, obtained as a yellow amorphous powder, the fused and crystalline form of which is called litharge; lead ocher. It is used as a pigment. It is also called lead oxide yellow, as opposed to red lead, which is lead tetroxide Pb3O4.
Note: Massicot is sometimes used by painters, and also as a drier in the composition of ointments and plasters.
Litharge \Lith"arge\ (l[i^]th"[.a]rj), n. [OE. litarge, F. litharge, L. lithargyrus, Gr. liqa`rgyros the scum or foam of silver; li`qos stone + 'a`rgyros silver. Litharge is found in silverbearing lead ore.] (Chem.) Lead monoxide; a yellowish red substance, obtained as an amorphous powder, or crystallized in fine scales, by heating lead moderately in a current of air or by calcining lead nitrate or carbonate. It is used in making flint glass, in glazing earthenware, in making red lead or minium, etc. Called also massicot.
n. (context chemistry English) lead monoxide, PbO, obtained as a yellow amorphous powder, the fused and crystalline form of which is called litharge; lead ocher. It is used as a pigment; also, ''lead oxide yellow'', as opposed to red lead, which is lead tetroxide Pb3O4.
n. the mineral form of lead monoxide; in the form of yellow powder it is used as a pigment [syn: massicotite]
Massicot is lead (II) oxide mineral with an orthorhombic lattice structure.
Lead(II) oxide (formula: PbO) can occur in one of two lattice formats, orthorhombic and tetragonal. The tetragonal form is called litharge. PbO can be changed from massicot to litharge (or vice versa) by controlled heating and cooling. At room temperature massicot forms soft ( Mohs hardness of 2) yellow to reddish-yellow, earthy, scaley masses which are very dense, with a specific gravity of 9.64. Massicot can be found as a natural mineral, though it is only found in minor quantities. In bygone centuries it was mined. Nowadays massicot arises during industrial processing of lead and lead oxides, especially in the glass industry, which is the biggest user of PbO.
The definition of massicot as orthorhombic PbO dates from the 1840s, but the substance massicot and the name massicot has been in use since the late medieval era. There is some evidence that the ancient Romans used the substance.
It may occur as an oxidation product of other lead-bearing minerals such as galena, bournonite, boulangerite, either naturally or in industrial processing. When massicot is found in a natural environment, some other minerals that may be found with it may include cerussite, litharge, minium, wulfenite, oxides of antimony and limonite.
Usage examples of "massicot".
Ores of Lead -- Geographical Distribution of the Lead Industry -- Chemical and Physical Properties of Lead -- Alloys of Lead -- Compounds of Lead -- Dressing of Lead Ores -- Smelting of Lead Ores -- Smelting in the Scotch or American Ore-hearth -- Smelting in the Shaft or Blast Furnace -- Condensation of Lead Fume -- Desilverisation, or the Separation of Silver from Argentiferous Lead -- Cupellation -- The Manufacture of Lead Pipes and Sheets -- Protoxide of Lead -- Litharge and Massicot -- Red Lead or Minium -- Lead Poisoning -- Lead Substitutes -- Zinc and its Compounds -- Pumice Stone -- Drying Oils and Siccatives -- Oil of Turpentine Resin -- Classification of Mineral Pigments -- Analysis of Raw and Finished Products -- Tables -- Index.
Sometimes, if I looked over his shoulder at the sky, and found the colors besides white in a cloud, or thought of grinding lead white or massicot, my breasts and belly tingled, and I pressed against him.
Gummage immediately supplied her with two bristle brushes, and sundry little shallow earthen cups, each containing a modicum of some sort of body color, massicot, flake-white, etc.