7-1 Fiber Manipulations: Removing Fibers from Tape and Mounting 7-2 Observing Effects of Mounting Media 7-3 Observing Fiber Shape, Surface and Internal Structure 7-4 Observing Color and
Pleochroism 7-5 Distinguishing Natural and Manufactured Fiber Classes
It is felt that in this case, by analogy with the optical phenomenon
pleochroism, one can observe the phenomenon of linear acoustic anisotropic absorption (LAAA) during propagation of shear waves.
Hornblende shows yellowish green to green and lamprobolite light brown to reddish brown
pleochroism, whereas both displays well developed sets of 56deg and 124deg cleavages in basal sections.
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Pleochroism, the Dichroscope and Colour Filters' then examines the range of colour filters available on the market today, along with the typical dichroscope and Chelsea Colour Filter.
Blue crystals exhibit a striking
pleochroism from colorless to "cornflower" blue, an optical attribute used to great effect by gem cutters.
Optical data: Biaxial (+), [alpha] 1.768, [beta] 1.771, [gamma] 1.818 (calc.), 2V(meas.) 29[degrees], dispersion not mentioned;
pleochroism not mentioned; X = b, Y ^ a = 5_ in obtuse angle [beta], Z ^ c = 9[degrees] in obtuse angle [beta].
Optical data: Biaxial (+), indices of refraction not given (the mean index of refraction calculated by the abstractor from the Gladstone-Dale relationship is 2.25), 2V(meas.) 86[degrees] given as 2[V.sub.x] which indicates biaxial (-), dispersion strong;
pleochroism X = light greenish yellow, Y = brown, Z = reddish brown; orientation not given.
Optical data: In reflected light: creamy, distinct anisotropism from light to dark creamy, no bireflectance,
pleochroism not given, [R.sub.1], [R.sub.2]: (47.0, 37.6 %) 480 nm, (48.2, 39.2 %) 540 nm, (49.6, 40.7 %) 580 nm, (52.3, 44.3 %) 660 nm.
It has no cleavage, is brittle with a conchoidal fracture and is transparent with strong
pleochroism. The hardness is 2.5 and the density 3.4.
Optical data: Uniaxial (-), [omega] 1.731, [epsilon] 1.719,
pleochroism strong, O dark red, E yellowish.