October 20, 2006
The avocado-colored mineral shown above are epidote crystals and were found near Santaquin, Utah. They're surrounded by tiny, cream colored feldspar crystals. These radiating, acicular epidote crystals formed when local garnet, amphibole, or pyroxene was subjected to retrograde (low-temperature) metamorphic conditions. As Precambrian plates collided and placed stresses on the rocks of central Utah, the transformation of minerals, such as epidote, records the processes within the restless lithosphere. Located in what is currently called the Santaquin Complex, the minerals, faults, and folds here continue to reveal their complex history.