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.
, 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.
The mineral is yellow-brown in plane-polarized transmitted light, isotropic with no pleochroism
, and n [much greater than] 1.8.
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.