April 2015 Microphoto of the Month
Vein in igneous rock. Fuzzy looking bundles of fibrous zeolite crystals growing in a vein in igneous rock. The shape of the crystal bundles suggest that the vein was open and filled with fluid when the crystals grew. It was later filled with feldspar, the clear mineral now occupying the center of the vein. The largest fuzzball is about 1 mm across.