ROCK & GEM FIELD GUIDE: Microcrystalline Quartz
BY RICHARD GROSS & PAM FREEMAN
W henmost people refer to quartz, they are referring to large single crystals. Microcrystalline quartz, however, is dense with crystal grains so small that an optical microscope is necessary to view the individual crystals. When those crystals are so small they cannot individually be seen using a specialized microscope, they are called cryptocrystalline.