MALACHITE, a bright green mineral, consisting of a basic copper carbonate, It belongs to the mono clinic system, but rarely forms good crystals, occurring mostly as nodular, botryoidal or reniform masses, with pronounced radial and concentric structure, successive layers often varying much in colour. It may also be quite compact or earthy and often forms thin films or mere stains on rocks. It is very commonly associated with the deep blue azurite (q.v.). The density is about 4 and the hardness 3.5-4.0. It is soluble in acids with effervescence.
Malachite is one of the commonest ores of copper and perhaps the most conspicuous, being a useful guide in prospecting. It is found in the upper oxidized portions of copper deposits, and is formed by the action of water, air and carbon dioxide on primary copper sulphides, especially where calcium carbonate is present. The soluble copper salts set free by oxidation of the sulphides react with limestone or other carbonates and precipitate the in soluble malachite. The mineral is found in nearly all copper mining districts : specially fine specimens have come from various mines in Russia, where it has often been used as a polished orna mental stone, though the colour is rather crude. Other well known localities for good specimens are the Copper Queen mine, Bisbee, Arizona, and the old Burra Burra mines, Kooringa, South Australia. (See also DYES, SYNTHETIC.) (R. H. RA.)
MALACHOWSKI, STANISLAW Polish statesman, the younger son of Stanislaw Malachowski, palatine of Posen. He was first elected a deputy to the Diet of 1764, and the Four Years' Diet unanimously elected him its speaker (1788). Malachowski worked tirelessly for reform and to save the republic. He was one of the framers of the constitution of May 3, 1791, exceeding in liberality all his colleagues and advocating the ex tension of the franchise to the towns and the emancipation of the serfs. In 1807 Malachowski was placed at the head of the executive committee appointed at Warsaw after its evacuation by the Prussians, and when the grand duchy of Warsaw was created Malachowski became president of the senate. In the ne gotiations with the Austrian government concerning the Galician salt-mines Malachowski assisted the treasury by hypothecating all his estates as an additional guarantee. In 1809 he died at Warsaw.
See August Sokolowski, Illustrated History of Poland (Pol.), vol. iv. (Vienna, 190o) ; Life and Memoirs of S. Malachowski, edited by Lucyan Siemienski (Pol.; Cracow, 1853).