Virtual Rock Kit

Explanation of Views

Hand specimen

a fist-sized piece of rock

Close-up

magnified view of the surface of a piece of rock

Thin section

a thin slice of rock seen under the microscope by transmitted light

Thin section under plane polars and crossed polars (x-polars)

The microscopes that geologists use to study thin sections of rock include two polarizing filters. The polarizing directions of the two filters are at right angles to each other. The lower polar is normally used and thin sections are viewed in "plane-polarized light" (light waves on one plane only). In plane-polarised light, minerals exhibit their "true" colour.

The upper polar (also known as an analyser) can be moved in and out of the path of light. When the upper polar is introduced into the path of light, the colour that is observed is an "interference colour" and not true colour. This is known as viewing the thin section under "crossed polars".

Rock in use

The rock in use in the built environment or within an industrial process

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