galena(redirected from Gallena)
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lead glance,lustrous, blue-gray mineral crystallizing usually in cubes, sometimes in octahedrons. It is the most important ore and the principal source of lead. It consists of lead sulfide, PbS, but frequently contains silver (it is mined for this metal in some localities) and other accessory metals. It is widely distributed throughout the world, occurring in veins and in bedded deposits, in Missouri, Idaho, Iowa, Wisconsin, and Utah in the United States (leading producer of lead) and in Australia, Canada, England, France, and Mexico. Galena crystals were once much used in radio "crystal" sets.
a mineral, lead sulfide (PbS), containing 86.6 percent lead.
Galena often occurs with admixtures of silver, bismuth, copper, zinc, or selenium. It crystallizes in a cubic system, producing separate crystals, dense masses, and granular aggregates. It is lead-gray in color with a metallic luster. Its hardness is 2.7-3 on the mineralogical scale, and its density is 7,400-7,600 kg/m3. Galena is an electrical conductor, and it shows a photoelectric effect that is sometimes positive and sometimes negative. It is diamagnetic. With a negative photoelectric effect it has detector properties. Galena is found in hydrothermal and some sedimentary deposits. In some cases, as in the Zavodinskoe bed in the Rudnyi Altai, galena forms almost monomineral ores, but more often it is accompanied by sphalerite, pyrite, and chalcopyrite. The largest deposits in the USSR are found in the Altai, the Northern Caucasus, Kazakhstan, Eastern Siberia, and Primor’e. It is found abroad in the USA, Canada, Australia, and countries of Africa. Galena is the principal ore used in lead smelting.