Muscovite

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green Bay



Plane-Polarized Light

Crossed Polarizers


Both muscovite and biotite are present in the plane-polarized view below. The muscovite is barely visible.

muscovp1.jpg (60636 bytes)

In crossed polarizers, muscovite generally has vivid second- and third-order colors.The interference colors of biotite are a bit lower order and more subdued because of biotite's coloration. Note the relative lack of mottling in the muscovite compared to the biotite.

MUSCOVX1.jpg (70937 bytes)

Where there are no dark minerals, muscovite in plane-polarized light is nearly invisible. It shows up only by its slightly higher relief than quartz and feldspar.

MUSCOVP2.jpg (48356 bytes)

The same field in crossed polarizers. The bright outlines are thin edges where the muscovite shows only first-order white colors because of its thinness.

MUSCOVX2.jpg (85388 bytes)

Below are two more fairly typical crossed-polarizer views of muscovite.

MUSC-X3.jpg (71752 bytes)

MUSC-X4.jpg (96486 bytes)


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Created 15 October 2009, Last Update