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Anthophyllite in Paint Under the Microscope

Anthophyllite Asbestos

This sample is from the white paint layer on the surface of a cellulose fiber acoustic ceiling tile. The sample is mounted in high dispersion 1.605 refractive index oil and a single linear polarizing filter is oriented parallel to the length of the fiber. The wavelength match here is about 480 nanometers. That indicates a D-line refractive index for the anthophyllite of about 1.620

Transmitted Phase Contrast with a Single Linear Polarizer Parallel to the Fiber Length


Anthophyllite asbestos is a fibrous amphibole with the chemical composition (Mg, Fe)7[Si8O22](OH, F)2. It is one of the more hazardous forms of asbestos.

Significance in the Environment:

Anthophyllite had a rather limited commercial use and is encountered as an impurity in talc as often as it is as an intentionally added material. In materials with a significant talc content the amount of Anthophyllite can exceed 1%.

Characteristic Features:

Anthophyllite has refractive indices that overlap those of Tremolite and Actinolite asbestos but Anthophyllite always shows parallel extinction.

Associated Particles:

As an impurity it is generally found with high concentrations of talc. It was used as an additive in paint and ceramics, mastics, floor tiles, acoustic tiles, and other construction materials.


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