In its vivid blue colour it contrasts strikingly with the emerald-green malachite, also a basic copper carbonate, but containing rather more water and less carbon dioxide.
Azurite occurs with malachite in the upper portions of deposits of copper ore, and owes its origin to the alteration of the sulphide or of native copper by water containing carbon dioxide and oxygen.
Being less hydrated than malachite it is itself liable to alteration into this mineral, and pseudomorphs of malachite after azurite are not uncommon.
Lastly, from the Altai region, as well as from the Nerchinsk Mountains, precious stones, such as jasper, malachite, beryl, dark quartz, and the like, are exported.
Many are found as minerals, the more important of such naturally occurring carbonates being cerussite (lead carbonate, PbC03), malachite and azurite (both basic copper carbonates), calamine (zinc carbonate, ZnCO 3), witherite (barium carbonate, BaCO 3), strontianite (strontium carbonate, SrC03), calcite (calcium carbonate, CaC03), dolomite (calcium magnesium carbonate, CaCO 3 MgCO 3), and sodium carbonate, Na 2 CO 3.
Diamonds are obtained in Borneo, garnets in Sumatra, Bachian and Timor, and topazes in Bachian, antimony in Borneo and the Philippines; lead in Sumatra, Borneo and the Philippines; copper and malachite in the Philippines, Timor, Borneo and Sumatra; and, most important of all, tin in Banka, Billiton and Singkep. Iron is pretty frequent in various forms. Gold is not uncommon in the older ranges of Sumatra, Banka, Celebes, Bachian, Timor and Borneo.
It is a constituent of the minerals cerussite, malachite, azurite, spathic iron ore, calamine, strontianite, witherite, calcite aragonite, limestone, &c. It may be prepared by burning carbon in excess of air or oxygen, by the direct decomposition of many carbonates by heat, and by the decomposition of carbonates with mineral acids, M2C03+2HC1=2MCl-FH 2 O+CO 2.
Heated with anhydrous sodium acetate and acetic anhydride it gives cinnamic acid; with ethyl bromide and sodium it forms triphenyl-carbinol (C 6 H 5) 3 C OH; with dimethylaniline and anhydrous zinc chloride it forms leuco-malachite green C6H5CH[C6H4N(CH3)2]2; and with dimethylaniline and concentrated hydrochloric acid it gives dimethylaminobenzhydrol, C 6 H 5 CH(OH)C 6 H 4 N(CH 3) 2.
The Devonian sandstones contain malachite ores near Kielce, and copper has been worked there since the 15th century, though the mines are now neglected.
Inland from Sur, and some seams of good coal in newer strata; sulphur occurs in a fairly pure state at Khamir and Bustaneh near Lingeh, and on Qishm I.; copper, as copper glance and malachite, occurs in the interior of Oman; copper-mines are said to have been worked in the neighbourhood of the coast near Lingeh by the Portuguese, but all trace of them has been lost.
Rosanilines and malachite greens derived from aminotriphenylmethanes, and aurins and phthaleins derived from oxytriphenylmethanes.
The principal ores of copper are the oxides cuprite and melaconite, the carbonates malachite and chessylite, the basic chloride atacamite, the silicate chrysocolla, the sulphides chalcocite, chalcopyrite, erubescite and tetrahedrite.
Malachite is a valuable ore containing about 56% of the metal; it is obtained in very large quantities from South Australia, Siberia and other localities.
Frequently intermixed with the green malachite is the blue carbonate chessylite or azurite, an ore containing when pure 55.16% of the metal.
Copper carbonates are of wide occurrence in the mineral kingdom, and constitute the valuable ores malachite and azurite.
Copper rust has the same composition as malachite; it results from the action of carbon dioxide and water on the metal.
These mountains are still the chief source of copper, but the ores, chiefly cuprite, malachite and chrysocolla, are also found in various parts of the Piedmont region.
Many semi-precious and precious stones are found in Utah, including garnet (long sold to tourists by the Navaho Indians), amethyst, jasper, topaz, tourmaline, opal, variscite (or " Utahlite "), malachite, diopside and Smithsonite.
Volcanic activity in the neighbourhood is further shown by the quantities of pumice-stone drifted on to the south coasts of Kandavu and Viti Levu; malachite, antimony and graphite, gold in small quantities, and specular iron-sand occur.
Minerals which were not mined commercially in 1902 include asbestos, which occurs in Spartanburg and Pickens counties; fullers'-earth; graphite in Spartanburg and Greenville counties; iron ores in the north and north-west portions of the state; iron pyrites in Spartanburg and York counties; talc, bismuth, ochre, pyrites, ' galena, brown coal, malachite, phosphate of lead and barytes.