Dec 27, 2021
MicROCKScopica
A thin (30µm) small (2 mm wide) slice of Brazilian agate. Agate is made of microcrystalline quartz, called chalcedony. In this image we can appreciate the origin of agate, that recalls that of incrustations in water pipes: silica-rich, hot solutions repeatedly deposit thin layers of chalcedony - very often as fibers arranged with a regular geometry - that vary in shape, color, transparency and thickness. Sometimes "dirty" solutions deposited dark, iron-rich linings that help track the progressive growth of the rock. Polarized light, crossed polarizers and lambda plate, width c. 2 mm.
