pyrrhotite
enUKpyr·rho·tite
P0691100 (pĭr′ə-tīt′) also pyr·rho·tine (-tīn′)pyrrhotite
(ˈpɪrəˌtaɪt) orpyrrhotine
pyr•rho•tite
(ˈpɪr əˌtaɪt)n.
Noun | 1. | ![]() |
单词 | pyrrhotite | |||
释义 | pyrrhotiteenUKpyr·rho·titeP0691100 (pĭr′ə-tīt′) also pyr·rho·tine (-tīn′)pyrrhotite(ˈpɪrəˌtaɪt) orpyrrhotinepyr•rho•tite(ˈpɪr əˌtaɪt)n.
pyrrhotiteenUKpyrrhotite(pĭr`ətīt) ormagnetic pyrites,bronze-yellow to bronze-red mineral, a sulfide of iron sometimes containing nickel. It tarnishes easily and is somewhat magnetic. It crystallizes in the hexagonal system, but appears usually in massive form, and occurs chiefly in basic igneous rocks. In some areas, e.g., at Sudbury, Ont., Canada, it is associated with pentlandite, an important ore of nickel. It is found also in the United States, Europe, and South America.Pyrrhotite(also pyrrhotine or magnetic pyrites), a sulfide mineral with composition Fe1-xS and containing admixtures of Ni and Co. Pyrrhotite’s crystal structure has hexagonal close packing of S atoms. It is defective, since not all the octahedral vacancies are occupied by Fe, as a result which certain Fe2+ are converted to Fe3+. The structural deficiency in Fe varies, and thus the compositions range from Fe0.875S (Fe7S8) to FeS (the stoichiometric composition FeS is known as troilite). The parameters and symmetry of the crystal cell vary according to the Fe deficiency and, when x ~ 0.11–0.2, pyrrhotite passes from the hexagonal modification to the monoclinic. Pyrrhotite is brownish yellow with dark brown streaks and has a metallic luster. It usually occurs in the form of solid masses or granular deposits composed of intergrowths of both modifications. It has a hardness of 3.5–4.5 on Mohs’ scale and a density of 4,580–4,700 kg/m3. Its magnetic properties vary according to composition: hexagonal pyrrhotites, which are deficient in S, are paramagnetic, while monoclinic varieties, which are rich in S, are ferromagnetic. Some pyrrhotite minerals display distinctive magnetic anisotropy—paramagnetism in one direction and ferromagnetism in the other, perpendicular to the former. Pyrrhotite is formed from hot solutions during a reduction in the concentration of dissociated S2– ions. It is widely distributed in hypogenic copper-nickel ore deposits associated with ultrabasic rocks, as well as in contact-metasomatic deposits and hydrothermal masses with copper-polymetallic, sulfide-cassiterite, and other types of mineralization. Pyrrhotite alters to pyrite, marcasite, and limonite in the zone of oxidation. REFERENCEMineraly, vol. 1, Moscow, 1960.G. P. BARSANOV pyrrhotite[′pir·ə‚tīt]pyrrhotiteenUK
Synonyms for pyrrhotite
|
|||
随便看 |
|
英语词典包含2567994条英英释义在线翻译词条,基本涵盖了全部常用单词的英英翻译及用法,是英语学习的有利工具。