Flaky
Pseudo-isotropic
Pseudo-isotropic
Description
Colorless to yellow or green, transparent, generally pleochroic. Low to moderate relief. Cleavage planes frequently visible as platy layers. Very low apparent birefringence (pseudo-isotropy) because flakes settle with {001} in the plane of the slide. However, by tilting the slide very slightly (e.g., by slipping another slide under the slide) one can evaluate the true birefringence (thanks to Frank Brown, U. Utah, for the tip). Chlorite has weak birefringence and can have anomalous (purplish or brown) interference colors due to its varying chemistry. Occurs as flakes larger than surrounding material when primary, can be fibrous or granular when replacing other minerals.
Colorless to yellow or green, transparent, generally pleochroic. Low to moderate relief. Cleavage planes frequently visible as platy layers. Very low apparent birefringence (pseudo-isotropy) because flakes settle with {001} in the plane of the slide. However, by tilting the slide very slightly (e.g., by slipping another slide under the slide) one can evaluate the true birefringence (thanks to Frank Brown, U. Utah, for the tip). Chlorite has weak birefringence and can have anomalous (purplish or brown) interference colors due to its varying chemistry. Occurs as flakes larger than surrounding material when primary, can be fibrous or granular when replacing other minerals.
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