Monoclinic Extinction is only parallel or symmetrical in sections parallel to the ortho axis [_=b_]; all other sections show extinction angles. Color distribution is only symmetrical to one line or to the central point, see p. 48. Triclinic Extinction angles in all sections, although in some minerals these angles may be very small. No symmetry in color distribution, see p. 48. ▄AGGREGATE.▄ Not homogeneous, but made up of an aggregation of individuals, all extinguishing at different times. Double Refraction (maximum).[155] 0.287 Rutile 0.179 Dolomite 0.172 Calcite 0.141 Titanite 0.090 Titanite 0.072 Hornblende (basaltic) 0.062 Zircon 0.058 Biotite 0.050 Talc 0.050 Ægirite 0.041 Muscovite 0.037 Epidote 0.036 Chrysolite (Olivine) 0.036 Scapolite (Meionite) 0.034 Tourmaline 0.034 Phlogopite 0.030 Allanite (Orthite) 0.029 Diopside 0.027 Actinolite 0.027 Tremolite 0.024 Hornblende (common) 0.024 Diallage 0.024 Anthophyllite 0.023 Augite 0.021 Sillimanite (Fibrolite) 0.018 Glaucophane 0.017 Tourmaline (precious) 0.016 Cyanite (Disthene) 0.013 Hypersthene 0.013 Scapolite (Marialite) 0.013 Anorthite 0.012 Natrolite 0.011 Chlorite (Clinochlore) 0.011 Andalusite 0.011 Topaz 0.010 Staurolite 0.010 Gypsum 0.010 Enstatite 0.010 Serpentine 0.009 Corundum 0.009 Iolite (Cordierite) 0.009 Quartz 0.008 Topaz 0.008 Kaolin 0.008 Labradorite, Ab_{1}An_{1} 0.008 Oligoclase, Ab_{4}An_{1} 0.008 Albite 0.007 Orthoclase 0.007 Microcline 0.006 Vesuvianite 0.005 Zoisite 0.004 Nephelite (Elæolite) 0.003 Apatite 0.003 Melilite 0.002 Tridymite 0.002 Leucite 0.002 Allanite (Orthite) 0.001 Chlorite (Penninite) 0.001 Vesuvianite Indices of Refraction (mean).[155] 2.712 Rutile 2.38 Perofskite 2.00 Spinel (Chrome) 1.963 Titanite 1.95 Zircon 1.920 Titanite 1.856 Garnet (Melanite) 1.792 Ægirite 1.78 Allanite (Orthite) 1.78 Garnet (Almandite) 1.766 Corundum 1.751 Epidote 1.75 Garnet (Pyrope) 1.741 Staurolite 1.723 Hypersthene 1.72 Spinel 1.720 Zoisite 1.720 Cyanite (Disthene) 1.719 Hornblende (basaltic) 1.715 Vesuvianite 1.711 Augite 1.699 Zoisite 1.697 Diopside 1.688 Diallage 1.675 Chrysolite (Olivine) 1.665 Enstatite 1.664 Sillimanite (Fibrolite) 1.674 Tourmaline 1.644 Anthophyllite 1.64 Hornblende (common) 1.637 Andalusite 1.635 Apatite 1.632 Glaucophane 1.632 Topaz 1.630 Melilite 1.633 Tourmaline (precious) 1.622 Dolomite 1.621 Actinolite 1.621 Tremolite 1.618 Biotite 1.608 Topaz 1.588 Chlorite (Clinochlore) 1.587 Muscovite 1.582 Anorthite