Optical Mineralogy

acute bisectrix Aegirine aggregates albite Andalusite anisotropic Antigorite Aragonite axes axial plane balsam Barite biaxial positive Biotite Birefringence bisectrix c-axis calcite Chalcedony cleavage traces Collophane color bands colored minerals Colorless in thin cross sections crossed nicols Cummingtonite determined Diopside dispersion Distinguishing Features double refraction Dumortierite Epidote euhedral euhedral crystals Extinction parallel feldspars figure is biaxial Fluorite Form fragments Gibbsite glass Glaucophane grains hexagonal Hornblende igneous rocks index ellipsoid indices of refraction interference colors isogyres Isometric isotropic large axial angle length-fast length-slow Leucite light liquids metamorphic microscope Monoclinic Mullite n₁ n₂ negative nepheline normal occurs olivine opal optic axis ordinary ray Orientation diagrams Orthorhombic parallel to 010 Perovskite Piedmontite plagioclase plane is 010 pleochroic polarized prism quartz quartz wedge Relief Rutile Schorlite Sillimanite slow ray Sodalite Spinel structure tetragonal thin sections tion triclinic Tridymite twin-plane twinning uniaxial minerals usually velocity vibrating parallel vibration directions wave ηβ