This Is Rock(ed) Science
Together with Cobus Visagie and his image of fungi, Dr. Bernardo Cesare, Professor of Petrology at the Department of Geosciences of the University of Padova (Italy), has been awarded third prize in our ZEISS Microscopy Image Contest for his image of a Brazilian agate.
Prof. Cesare is a petrologist – a geologist specialized in the study of metamorphic rocks – which are rocks that have been substantially changed from their original form due to combinations of high heat, high pressure and/or hot mineral-rich fluids.
Tell us about your profession and the submitted agate image.
I have been studying rocks for 35 years using polarized microscopy as a fundamental tool for my research. Over the years, I have developed aesthetic photomicrography as a side activity. The awarded image is one of my best recent images. It shows a very special Brazilian agate made of extremely fine-grained quartz (chalcedony), which is much finer than in common agates.
Agate from Brazil
What was the most challenging part of acquiring an image such as this?
The very fine grain-size (about 10 µm) is apparent in the central and upper bands of the image. The first challenge with such an image concerns sample preparation, because agates are very hard so cutting, grinding and polishing them becomes a nightmare for the thin section manufacturers. The second challenge is obtaining a sharp focused image because the grain size is smaller than the sample thickness: this induces a little bit of blur in the central and upper bands of the photo.
What is special about this image?
I love this image because of the unique sample it comes from. With the horizontal banding and the coarser quartz crystals in the lower part resembling a crowd (some might see penguins), it has been appropriately named The Concert. Viewers find this image and the title very evocative.
Along with an exciting geological history, every piece of rock hides a universe of colors and shapes that can be disclosed with a polarized microscope.