（本科）3 矿物鉴定实习ppt课件.pptx

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1、课程主讲人：3 矿物鉴定实习西南交通大学 赵晓彦第三讲 矿物鉴定实习1矿物鉴定程序2鉴定特征的获取4矿物鉴定作业本讲内容3代表性矿物鉴定举例1 矿物的鉴定程序 引入N-C方法进行矿物的鉴定，共分4步：(1) 鉴定光泽，确定矿物的关泽是“金属光泽”或“非金属光泽”(2) 鉴定硬度，确定矿物的硬度是“ 5.5”或 “ 5.5”； (3) 鉴定条痕，确定矿物的条痕是“彩色”或“白色”；(4) 鉴定解理，确定矿物 “无解理” 或“一组及多组解理”。1 矿物的鉴定程序HardnessStreakCleavageOther propertiesMineralLess than 5.5Black, gree

2、nish black, brownish black, or grayOne (but not always visible)Gray to black; H = 1; S.G. = 2.5; may have dull luster; greasy feel; soils paper and fingers, also in Table 2-6.Graphite (C)Three (excellent cubic cleavage)Silver gray, H = 2.5; S.G. =7.5; cubic crystals common.Galena (PbS)NoneBlack to b

3、rownish black; H = 5.5; S.G. = 4.6; luster may be almost nonmetallic; brownish-black streak; weakly magnetic.Chromite (FeCr2O4)NoneGolden yellow or greenish yellow; H = 3.54; S.G. = 4.2; massive.Chalcopyrite (CuFeS2)Yellow-brownNoneDark brown to black; H = 55.5; S.G. =4; massive or rounded forms wit

4、h radiating, fiber-like layers.GoethiteFeO(OH)Copper-redNoneCopper to brown, may have green coating; H = 2.53; S.G. = 8.9; malleable, sectile.Native copper(Cu)Greater than 5.5Greenish black to blackNoneBrass-yellow; H = 66.5; S.G. = 5; massive or as crystals (cube, pyritohedron)Pyrite(FeS2)Black Non

5、eDark-gray to black; H = 6; S.G. = 5.2; may have dull luster if surface not fresh; attracted to magnet.Magnetite(Fe3O4)Red-brownNoneSteel gray to dull red; H = 6; S.G. = 5; may be micaceous (tiny flakes) or massive, also in table 2-6.Hematite(Fe2O3)表2-5 金属光泽矿物的鉴定 1 矿物的鉴定程序表2-6 非金属光泽、硬度5.5、彩色条痕矿物的鉴定

6、StreakCleavageOther propertiesMineralGray-black One (but not always visible)Gray to black; H = 1; S.G. = 2.5; may have dull luster; greasy feel; soils paper and fingers, also in Table 2-5.Graphite (C)Red-brownNoneRed to reddish brown; H = 1.55.5; S.G. = 5; dull luster; earthy or oolitic (containing

7、spherical structures having diameters of 0.25 to 2 mm) masses, also in table 2-5.Hematite(Fe2O3)Yellow-brownNoneYellow-brown, orange-brown to dark brown; H = 1.5 5.5; S.G. = 3.6 4.0; dull luster; earthy, may be a rustlike coating. Not a true mineral, limonite is a general name for several rustlike,

8、hydrous iron oxides.Limonite (Various hydrous iron oxides)YellowNoneYellow; H = 1.52.5; S.G. = 2.1; resinous or vitreous luster.Sulfur (S)Six - may be difficult to countLight yellow, yellowish brown, black; H = 3.5 4; S.G. = 4.0; resinous or vitreous luster; faint odor of hydrogen sulfide (rotten eg

9、gs)Sphalerite(ZnS)BlueNoneAzure blue; H = 3.5 4; S.G. = 3.8; occurs as coating, masses, or tiny crystals, commonly with malachite, and commonly as an accessory mineral.AzuriteCu3(CO3)2(OH)2GreenNoneBright green; H = 3.5 4; S.G. = 4; occurs as coating, masses, or tiny crystals, commonly with azurite,

10、 and commonly as an accessory mineral.MalachiteCu2CO3(OH)21 矿物的鉴定程序表2-7 非金属光泽、硬度5.5、白色或浅色条痕、无解理矿物的鉴定 CleavageOther propertiesMineralNone or Indistinct White, may have a brownish tint, H = 1 2.5; S.G. = 2.6; dull luster; greasy feel, earthy odor, powdery.Kaolinte(Al2Si2O5(OH)4)White, gray, or apple g

11、reen; pearly luster; H = 1 (or 2 in some impure varieties); S.G. = 2.72.8; greasy feel; may have light gray streak; also in Table 2-8.Talc (Mg3Si4O10(OH)2)White, H = 2; S.G. = 2.3; satiny or silky luster and fibrous fracture indicates satin spar variety of gypsum. An opaque, white or gray, massive v

12、ariety is alabaster; also in Table 2-8.Gypsum(CaSO42H2O)Reddish brown to brown color; H = 1 6; S.G. = 2.02.5; dull to earthy luster; massive or with pea-shaped structures; may scratch glass with difficulty. Not a true mineral, but a rock consisting of several similar minerals. May have faint, red-br

13、own streak, also in Table 2-9.Bauxite (Mixture of hydrous aluminum oxides)Multicolored green, gray, black; H = 3 5; S.G. = 2.52.6; dull to greasy luster; slight greasy feel; massive to fibrous (asbestos).Serpentine(Mg3Si2O5(OH)4)Light green to medium green, brown, yellow; vitreous luster; H = 5; S.G

14、. = 3.2; six-sided crystals common; may show one poor cleavage.Apatite Ca5(PO4)3(F,Cl,OH)Buff, gray, white, pinkish; H = 3.5 4; S.G. = 2.82.9; small, rhombohedral crystals or massive; three cleavages, not at 90, may be indistinct in massive varieties; reacts slowly or not at all with dilute hydrochl

15、oric acid unless powdered. Also in Table 2-8. Dolomite(CaMg(CO3)2)1 矿物的鉴定程序表2-8 非金属光泽、硬度5.5、无解理矿物的鉴定 CleavageOther propertiesMineralNoneBrown, pink, blue, gray; H = 9; S.G. = 4; Six-sided prismatic crystals: ruby (red) and sapphire (commonly blue) are gem varieties.Corundum (Al2O3)Black, pink, blue,

16、 green, brown; vitreous luster; H = 77.5; S.G. = 33.3; slender crystals with triangular cross sections and striated sides.Tourmaline (Complex hydrous silicate)Reddish brown, yellowish tan; vitreous luster; H= 6.57.5; S.G. = 3.6 4.3; twelve sided crystals common. Broken surfaces may resemble cleavage

17、 in some samples. Garnet(Ca-Mg-Fe-Al silicate)Red-brown to brownish black; vitreous luster, or dull luster; H= 77.5; S.G. = 3.7; prismatic and X- or cross-shaped crystals.Staurolite(Fe-Al silicate)Coarsely crystalline varieties: clear, milky, white, purple, smoky, pink; transparent to translucent; v

18、itreous luster; H = 7; S.G. = 2.7; conchoidal fracture; usually massive; sometimes occurs as six sided crystals; microcrystalline varieties; chert (gray, dull luster), flint (black, dull luster), chalcedony (brown to gray, translucent, waxy luster), agate and anyx (yaricolored bands, vitreous luster

19、). Quartz (SiO2)Colorless, white, or pale shades of yellow, green, red, or blue, may show play of colors; vitreous to resinous luster; H = 56; S.G. = 22.3; rounded forms common, but also massive; conchoidal fracture. A mineraloid. Opal (SiO2nH2O)Olive green to yellow green; vitreous to dull luster;

20、H = 6.57 but difficult to test because of granular; S.G. = 3.34.4;Olivine (Mg, Fe)2SiO4Reddish brown to brown color; H = 16; S.G. = 2.02.5; dull to earthy luster; massive or with pea-shaped structures; may scratch glass with difficulty. Not a true mineral, but a rock consisting of several similar mi

21、nerals. Also in Table 2-7.Bauxite (Mixture of hydrous aluminum oxides)1 矿物的鉴定程序表2-10 非金属光泽、硬度5.5、有解理矿物的鉴定 CleavageOther propertiesMineralOneGreen, blue, cyan, yellow, colorless (pure beryl), red and others; H = 7.58; S.G. = 2.72.9; prismatic to tabular, radial, columnar crystals; granular to compact

22、 massive; vitreous luster; mostly transparent; one poor cleavage; an optical reflectance of chatoyancy; white streak; brittle; beryl of various colors is found most commonly in granitic pegmatites, or in mica schists and limestone; varieties of beryl are well-known gemstones including emerald (green

23、 beryl), aquamarine (blue or cyan bery), goshenite (colorless), golden beryl and red beryl. Beryl Be3Al2(SiO3)6Colorless (pure topaz), blue, brown, orange, gray, yellow, green, pink and reddish pink; H = 8; S.G. = 3.3; the hardest silicate mineral; prismatic crystals with faces striated parallel to

24、long dimension; columnar, compact, massive; vitreous luster; transparent; white streak; one perfect cleavage; topaz is commonly associated with siliceous igneous rocks of the granite and rhyolite type; topaz is wide used in jewellery as a cut gemstone due to its hardness and transparence;Topaz Al2Si

25、O4(F,OH)2TwoBlack to dark green; H = 56; S.G. = 3.23.4; vitreous to dull luster; two imperfect cleavages meet at nearly 90. Tend to look “blocky”, not splintery. A pyroxene. Another pyroxene, diopside, is similar but is light grayish green. Also in Table 2-8.Augite (Ca-Mg-Fe silicate)Black; H = 56;

26、S.G. = 33.4; vitreous luster; two perfect cleavages meet at 124 and 56; cleavage faces stepped rather than smooth; splintery appearance; may have greenish black to black streak. An amphibole also listed in Table 2-10.Hornblende (silicates)Colorless, greenish, grayish yellow, white, pink; H = 6; S.G.

27、 = 2.5; columnar or tabular crystals; anhedral or euhedral; vitreous luster; transparent to translucent; white streak and uneven fractures; two perfect cleavages at 90; low negative relief under microscope; orthoclase is commonly associated with quartz in granites; orthoclase commonly alters to seri

28、cite or clay;Orthoclase(KAlSi3O8)White, gray, bluish white, reddish white, greenish white; H = 66.5; S.G.= 2.62.8; columnar or tabular crystals; vitreous luster; transparent to translucent; white streak; two perfect cleavages at 86, or one perfect cleavage plus one good cleavage; plagioclase is a se

29、ries of tectosilicate (framework silicate) minerals within the feldspar group, including anorthite (90-100 An%), bytownite (70-90 An%), labradorite (50-70 An%), andesine (30-50 An%), oligoclase (10-30 An%) and albite (0-10 An%); plagioclase is commonly coexisted with amphibole and augite in dark-col

30、ored igneous rocks, such as diorite and gabbro. PlagioclaseNaAlSi3O8- CaAl2Si2O8Reddish brown, yellow, green, blue, gray, colorless; H = 7.5; S.G.= 4.64.7; tabular to prismatic crystals; vitreous to adamantine luster; white streak; transparent to opaque; conchoidal to uneven fracture; two poor cleav

31、ages; zircon is an accessory mineral in igneous and metamorphic rocks, with crystals of large sizes in mafic pegmatites and carbonatites; zircon contains trace amounts of uranium and thorium (from 10 ppm up to 1 wt%), and it can be dated using several modern analytical techniques.Zircon (ZrSiO4)Thre

32、eReddish brown, red, pale yellow, pale blue, violet, rarely grass-green; H = 66.5; S.G.= 4.23, increasing with Nb-Ta content; acicular to prismatic, elongated and striated crystals; adamantine luster; opaque; white or bright red to dark red streak; brittle; one perfect cleavage plus two good cleavag

33、es; strongly anisotropism; rutile is a common high-temperature and high-pressure accessory mineral in anorthosite, and granite pegmatite; rutile has one of the highest refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large birefringence and high dispers

34、ion.Rutile(TiO2)2 鉴定特征的获取光泽：肉眼观察。硬度： 采用小铁刀刻划，若可以被小铁刀刻划出刻痕，则硬度小于5.5，否则硬度大于5.5； 将矿物在普通硅酸盐玻璃上刻划，如不能将玻璃刻划出刻痕，在玻璃上留下矿物的粉末，则矿物硬度小于5.5，如能将玻璃刻划出刻痕，则矿物硬度大于5.5。条痕：用矿物刻划普通硅酸盐玻璃或无釉瓷板，肉眼观察粉末的颜色。解理：肉眼观察。3 代表性矿物举例标本代号：3。光泽：非金属光泽硬度： 采用小铁刀刻划，小铁刀不能将矿物刻划出刻痕，硬度大于5.5；矿物能将玻璃刻划出刻痕，矿物硬度大于5.5。条痕：硬度大于5.5，故无条痕。解理：无解理。综上，应查表2-

35、93 代表性矿物举例标本代号：3。其他特征： 油脂或蜡状光泽 贝壳状断口； 透明； 无色。结论：石英表2-9 非金属光泽、硬度5.5、无解理矿物的鉴定 CleavageOther propertiesMineralNoneBrown, pink, blue, gray; H = 9; S.G. = 4; Six-sided prismatic crystals: ruby (red) and sapphire (commonly blue) are gem varieties.Corundum (Al2O3)Black, pink, blue, green, brown; vitreous l

36、uster; H = 77.5; S.G. = 33.3; slender crystals with triangular cross sections and striated sides.Tourmaline (Complex hydrous silicate)Reddish brown, yellowish tan; vitreous luster; H= 6.57.5; S.G. = 3.6 4.3; twelve sided crystals common. Broken surfaces may resemble cleavage in some samples. Garnet(

37、Ca-Mg-Fe-Al silicate)Red-brown to brownish black; vitreous luster, or dull luster; H= 77.5; S.G. = 3.7; prismatic and X- or cross-shaped crystals.Staurolite(Fe-Al silicate)Coarsely crystalline varieties: clear, milky, white, purple, smoky, pink; transparent to translucent; vitreous luster; H = 7; S.

38、G. = 2.7; conchoidal fracture; usually massive; sometimes occurs as six sided crystals; microcrystalline varieties; chert (gray, dull luster), flint (black, dull luster), chalcedony (brown to gray, translucent, waxy luster), agate and anyx (yaricolored bands, vitreous luster). Quartz (SiO2)Colorless

39、, white, or pale shades of yellow, green, red, or blue, may show play of colors; vitreous to resinous luster; H = 56; S.G. = 22.3; rounded forms common, but also massive; conchoidal fracture. A mineraloid. Opal (SiO2nH2O)Olive green to yellow green; vitreous to dull luster; H = 6.57 but difficult to

40、 test because of granular; S.G. = 3.34.4;Olivine (Mg, Fe)2SiO4Reddish brown to brown color; H = 16; S.G. = 2.02.5; dull to earthy luster; massive or with pea-shaped structures; may scratch glass with difficulty. Not a true mineral, but a rock consisting of several similar minerals. Also in Table 2-7.Bauxite (Mixture of hydrous aluminum oxides)4 作业矿物代号第一步鉴定结果第二步鉴定结果第三步鉴定结果第四步鉴定结果表格序号其他特征鉴定结论1245689101112141620