anorthite vs kaolinite vs chloritoid

anorthite (mineral) | kaolinite (mineral) | chloritoid (mineral)

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| anorthite | kaolinite | chloritoid alternate names | ab0 | amphodelite | anorthoîte | anortite | barsovite | beffanite | beffonite | biotine | calciclase | calcium feldspar | christianite | cyclopite | didymolite | indianite | latrobite | lepolite | lime-feldspar | thiorsauite | plagioclase (An90-100) | carnat | china clay | cleîte | collyrum | fireclay | kaolin | neokaolin | pholerite | barytophyllite | bliabergite | bliabergsite | chlorite spar | chloritoidite | sismondine | sismondite formula | CaAl_2Si_2O_8 | Al_2Si_2O_5(OH)_4 | (Fe^(2+), Mg, Mn)_2Al_4Si_2O_10(OH)_4 discovery year | 1823 | |

| anorthite | kaolinite | chloritoid density | 2.735 g/cm^3 | 2.6 g/cm^3 | 3.545 g/cm^3 transparency | transparent | subtransparent | translucent | transparent | translucent | transparent | translucent birefringence | 0.0115 | 0.007 | 0.0135 luster | vitreous | waxy | pearly | dull | earthy | vitreous | pearly Mohs hardness | 6.25 | 1.75 | 6.5 tenacity | brittle | sectile | streak | white | white | colorless green gray magnetism | nonmagnetic | nonmagnetic | nonmagnetic color | colorless | gray | white | red | reddish gray | white | brownish white | grayish white | yellowish white | grayish green | green gray | green black | grayish black | dark green | dark gray fracture | uneven | earthy | brittle molar mass | 277.4 g/mol | 258.2 g/mol | 484.7 g/mol

| anorthite | kaolinite | chloritoid Strunz ID | VIII/J.07-70 | VIII/H.25-10 | VIII/B.24-20 Dana ID | 76.1.3.6 | 71.1.1.2 | 52.3.3.1

| anorthite | kaolinite | chloritoid crystal system | triclinic | triclinic | triclinic crystal class | 1 | 1 | 1 unit cell volume | 1340 Å^3 (cubic ångströms) | 327.4 Å^3 (cubic ångströms) | 463.4 Å^3 (cubic ångströms) d-spacing | 3.2 Å (ångströms) | 3.18 Å (ångströms) | 4.04 Å (ångströms) | 7.17 Å (ångströms) | 1.49 Å (ångströms) | 3.58 Å (ångströms) | 4.47 Å (ångströms) | 2.46 Å (ångströms) | 2.97 Å (ångströms) intensity | 100% | 75% | 60% | 100% | 90% | 80% | 100% | 90% | 80% molecules per unit cell | 8 molecules per cell | 2 molecules per cell | 2 molecules per cell 2V angle | 13 π/30 radians≈78° (degrees) | 37 π/180 radians≈37° (degrees) | 25 π/72 radians≈125/2° (degrees) refractive indices | 1.574 | 1.581 | 1.586 | 0 | 0 | 0 | 1.558 | 1.564 | 1.565 | 0 | 0 | 0 | 1.722 | 1.727 | 1.732 | 0 | 0 | 0 dispersion | weak | none | r > v unit cell lengths | 8.177 Å (ångströms) | 12.88 Å (ångströms) | 14.17 Å (ångströms) | 5.14 Å (ångströms) | 8.93 Å (ångströms) | 7.37 Å (ångströms) | 9.5 Å (ångströms) | 5.48 Å (ångströms) | 9.16 Å (ångströms) unit cell angles | 93.17° (degrees) | 115.9° (degrees) | 91.22° (degrees) | 91.8° (degrees) | 104.5° (degrees) | 90.02° (degrees) | 96.88° (degrees) | 101.8° (degrees) | 90.03° (degrees)

Anorthite is the calcium endmember of the plagioclase feldspar mineral series. The chemical formula of pure anorthite is CaAl_2Si_2O_8. Anorthite is found in mafic igneous rocks. Anorthite is rare on the Earth but abundant on the Moon.

Kaolinite is a clay mineral, part of the group of industrial minerals with the chemical composition Al_2Si_2O_5(OH)_4. It is a layered silicate mineral, with one tetrahedral sheet of silica (SiO 4) linked through oxygen atoms to one octahedral sheet of alumina (AlO 6) octahedra. Rocks that are rich in kaolinite are known as kaolin or china clay.

Chloritoid is a silicate mineral of metamorphic origin. It is an iron magnesium manganese alumino-silicate hydroxide with formula: (Fe, Mg, Mn)_2Al_4Si_2O_10(OH)_4. It occurs as greenish grey to black platy micaceous crystals and foliated masses. Its Mohs hardness is 6.5, unusually high for a platy mineral, and it has a specific gravity of 3.52 to 3.57. It typically occurs in phyllites, schists and marbles.