Photomicroscopy: Crossing the polars

Photomicrographs in plane and polarized light provide more information about a specimen than either one alone. A simple way to display both plane and crossed polarized light images over the web is by using a rollover. A rollover is where the image source (in this case the photomicrograph) changes when the mouse moves over the image. Rollovers can be implemented using a simple java script on a web page. Adobe Acrobat Reader 5.0 also supports rollovers using the Acrobat frame tool.


To view this image rollover, your browser must must interpret Java (e.g. Netscape 4, Explorer 4 or later).

This is a photomicrograph of a sillimanite+garnet+biotite gneiss from central Massachusetts, USA. Note that the sillimanite inclusions in garnet are restricted to the outer rim of the garnet, a feature that is difficult to ascertain in plane light, and is greatly enhanced in the crossed polars image. Move your mouse in and out of the image to see it change.

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