Halloysite, Al2(Si2O5)(OH)4, Quartz, Cabiche, Quípama Municipality, Boyacá Department, Colombia. Halloysite yellow inclusions in Quartz crystals. This specimen of "Mango" quartz has been nicknamed "The Fan". Size 15.2 x 12 x 8.4 cm. H. Rivera photograph. Photo from Mindat.org
Halloysite, Al2(Si2O5)(OH)4, Quartz, Cabiche, Quípama Municipality, Boyacá Department, Colombia. Halloysite yellow inclusions in Quartz crystals. This specimen of "Mango" Quartz has been nicknamed "The Fan". Size 15.2 x 12 x 8.4 cm. H. Rivera photograph. Photo from Mindat.org
Calcite with quartz from the Huanggang Mine, Inner Mongolia, China. Photo by Jeffrey A. Scovil.Julie Columnar Basalt. Meshgin-shahr, NW Iran. Columnar Basalt can form when lava cools in underground flows. These are later revealed when the surrounding rock weathers away.
