The mineral:

is isotropic or weakly anisotropic, with low relief.

is isotropic or weakly anisotropic, with high relief.

shows paralell and mottled extinction.

has basal sections with two intersecting cleavages.

When rotating the stage, CHANGES ITS RELIEF from low to medium/high: it is a carbonate. It is not possible to differentiate calcite, dolomite, siderite, magnesite and rhodochrosite from each other under the petrographic microscope.


in PPL is colorless and in CPL shows anomalous interference colors, which are not found in the Michel-Levy interference color chart.

in PPL is colorless and has low or medium relief; in CPL has lower 1st order colors and is UNIAXIAL.

in PPL is colorless and has low or medium relief; in CPL has lower 1st order colors and is BIAXIAL.

in PPL is colorless and has low or medium relief; in CPL shows colors higher than lower 1st order.

in PPL is colorless and has moderate to high relief; in CPL shows colors of lower 1st order.

in PPL is colorless and has moderate to high relief; in CPL shows colors higher than lower 1st order.

in PPL is colored and has NO pleochroism or has barely perceptible pleochroism.

in PPL is pleochroic in pale green colors.

in PPL is pleochroic in intense GREEN colors, may be brownish or yellowish.

in PPL is pleochroic in dominantly RED colors, may be brownish.

in PPL is pleochroic in dominantly BROWN colors, may be reddish.

in PPL is pleochroic in dominantly YELLOW colors, may be orange.

in PPL is pleochroic in dominantly ORANGE colors, may be yellowish.

in PPL is pleochroic in dominantly BLUE colors.

in PPL is pleochroic in PINK colors.

Rarer pleochroisms of various colors in different minerals.

Back to alphabetical index.