Rainbow Turgite from Graves Mountain, Georgia

Turgite is a fascinating and beautiful material.  It often occurs as rainbow-colored iridescent coatings on iron oxide-rich rocks or rocks having surface iron oxide staining.  It can also occur as irregular botryoidal formations. The exact nature of the material called turgite has not agreed upon.  Some mineralogists believe turgite is not a mineral. They surmise it's a mixture of hematite and goethite resulting from goethite alteration.  Others say turgite is a hydrous hematite mineral.

Turgite was at one time a valid mineral species, but has since been discredited and is now defined as either Hematite or Goethite (or a combination of these two iron oxides), sometimes showing a botryoidal habit with rainbow iridescence. Turgite is not classified by the International Mineralogical Union (IMU). Turgite is generally accepted to be a mixture of Hematite and Goethite. Hematite is an iron oxide mineral which occurs in most metamorphic and sedimentary rocks. Goethite is a hydrated iron oxide mineral and forms in hydrothermal deposits and is a common mineral.

In any case these beautiful and unique Rainbow Turgites from Graves Mountain, Georgia are famous and are high-quality specimens. This locale is part of the Carolina Slate Belt of the Appalachian Mountains . The Appalachian Mountains of southeastern USA formed during the ancient  continental collision between Africa and North America. Allard (1999) characterizes the Graves Mountain locality as a metamorphosed hydrothermal system.