Agate Microscape #1

There was a penetration of the light into solid substance so that I seemed to see into things, deep in....... more

by - MicROCKScopica -

Title

Agate Microscape #1

Artist

- MicROCKScopica -

Medium

Photograph - Polarized Light Photomicrograph

Description

"There was a penetration of the light into solid substance so that I seemed to see into things, deep in...".
John Steinbeck was not thinking of rocks when he wrote this sentence in "Travels with Charley - In search of America". However, his feeling exactly reflects what people should think when looking at rock photomicrographs such as in this reportage on Agates from Lake SUperior (USA), kindly provided by John D. Marshall and Denise Harrison.
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This is an unusual reportage that discloses the secret, marvelous world hidden within stones. I will show how rocks look like when they are seen from within and with the help of a polarizing microscope.
The stone chosen for this reportage is an "Agate" from Lake Superior. Agate is beautiful also when seen with the naked eye, as in macro images: like the quartz sand grains, agate is made of silica (SiO2), but in a microcrystalline variety called chalcedony.
The origin of agate is a very similar to that of incrustations in water pipes: silica-rich, hot solutions repeatedly deposit thin layers of calcedony that vary in shape, color, transparency and thickness. Sometimes a lining of crystalline quartz is present, like in the center of the image.
The photomicrographs illustrate such amazing variety with the help of interference colors. These are not an artifact but the result of the propagation of polarized light within minerals. Each image represents a fragment of agate a few millimeters across. This agate was sliced down to 30 micrometers, the conventional thickness at which geologists use to study rocks at the microscope.
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All images are transmitted, polarized light photomicrographs of 30-micron-thick rock slices (geological "thin sections"), with width of view ranging from 1 to 5 mm. Images were taken with a Zeiss Axiocam Mr5 camera mounted on the trinocular head of a Zeiss Axioscop 40 Pol microscope.

Technique: Photomicrograph under polarized light, crossed polars plus red tint plate.

Uploaded

September 1st, 2018