Uniaxial figures
Glazer, A. M. and
Cox, K. G.,
International Tables for Crystallography
(2013).
Vol. D,
Section 1.6.4.12,
p.
[ doi:10.1107/97809553602060000905 ]
will be obvious because all colours lie well within the first order (Figs.
1.6.4.9 a and b) . Fig.
1.6.4.10 (a) illustrates, by reference to the indicatrix, the way in which the vibration directions of the o and e rays are disposed ...
Vibration directions
Glazer, A. M. and
Cox, K. G.,
International Tables for Crystallography
(2013).
Vol. D,
Section 1.6.4.4,
p.
[ doi:10.1107/97809553602060000905 ]
the phenomenon known as pleochroism – see Fig.
1.6.4.1).
Figure
1.6.4.1
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A thin section of a rock containing the minerals aegirine (elongated crystals) and eudyalite (the matrix) viewed in plane ...
Other methods of measuring birefringence
Glazer, A. M. and
Cox, K. G.,
International Tables for Crystallography
(2013).
Vol. D,
Section 1.6.4.10,
p.
[ doi:10.1107/97809553602060000905 ]
crystal to change their effective retardation in order to compensate against the retardation of the specimen. The Berek compensator uses a
calcite plate 0.01 mm thick, whereas the Ehringhaus compensator has compound compensating plates ...
Practical observation of crystals
Glazer, A. M. and
Cox, K. G.,
International Tables for Crystallography
(2013).
Vol. D,
Section 1.6.4,
p.
[ doi:10.1107/97809553602060000905 ]
required are straight lines. The vibration directions for the complete figure are given in Fig.
1.6.4.12 (c).
Considering first the isogyres (brushes), if the optic axial plane lies N–S, as in Fig.
1.6.4.13 (a), clearly the isogyres ...
