Andalusite Thin Section

In thin section the square and elongate andalusite crystals are white in ppl and low first order colours between crossed polars.

Andalusite thin section. All three of these minerals have the same combination of chemical elements as indicated by the chemical formula al 2 sio 5. Andalusite crystals are 1 cm in diameter sepahi et al 2004. The rock is metamorphosed slate thermally altered by a shallow granite intrusion.

In thin section andalusite is colorless in plane light and first order colors typically gray to pale yellow under crossed polars. Note the very clear dark inclusions that form a cross and the low 1st order gray of the interference color. Although commonly light yellow green in thin section it may be colorless.

Andalusite in hand sample clicking on some images leads to larger versions andalusite chiastolite from a graphitic schist hamadan iran. Andalusite is the least dense of this group having been formed under. Colourless rarely pink moderate relief two cleavages at 90 o low order interference colours.

It is colourless in thin section with moderate relief. Key optical features of andalusite in thin section. Photomicrograph of andalusite in thin section in crossed polarized light.

The images below show a subhedral basal section with typical cross shaped inclusions the variety known as chiastolite. Sillimanite needle like shape higher order interference colours kyanite higher relief more prominent cleavage. Its interference colors commonly seem anomalously bright compared to.

Andalusite in spotted slate. Alex strekeisen i vetrini della mia fantasia. Note the diamond shaped inclusion cloud to the bottom left at the crystal center and the inclusion trails that radiate from the corners of the diamond.