Rhodolite
Rhodolite is a rose-pink to red variety of Pyrope, which is a species in the Garnet Group. The name Rhodolite originally referred only to a variety of Pyrope Garnet but these days the name is used to describe just about any pink to red Garnet in the Almandine-Pyrope series. Chemically, Rhodolite can be pure Pyrope but may also be a mixture of about 70% Pyrope and 30% Almandine. Rhodolite gems vary in color from a rose-pink to purple-pink or purple-red and also raspberry-red. Many common red Garnets tend to be a very deep red with a brownish tint but Rhodolite is lighter and brighter because of its excellent clarity and relatively high refractive index (RI). One source of Rhodolite gems is the renowned Umba River Valley in Tanzania. Rhodolite gems from this area are often called Umbalite. A purplish varity of Rhodolite called “Grape Garnet” has been found in Brazil.
Rhodolite was discovered in 1893 at Cowee Creek and Masons Branch Brook, Cowee Valley, Macon County, North Carolina, USA by Mr. A. M. Field of Asheville, North Carolina and was believed to be a variety of Almandine. It wasn’t until analysis by William Earl Hidden (1853-1918) and Joseph Hyde Pratt (1870-1942) in 1898 that it was determined to be a variety of mostly Pyrope. Rhodolite was named in 1898 by Hidden and Pratt from the Greek words ρόδον (rhodo), meaning rose, and λίθος (lithos) meaning stone, referring to its common rose color.
Rhodolite Garnet distribution: at Brumado, Bahia, Brazil. At Lokirima, Lodwar, Turkana District, Rift Valley Province, Kenya. In the US at Masons Branch, Macon County, North Carolina. Also found in Burma (Myanmar), China, Madagascar, Mozambique, Norway, South Africa, Sri Lanka and Tanzania.
| Category: | Pyrope variety, nesosilicate |
| Chemical Formula: | Mg3Al2(SiO4)3 Magnesium Aluminum Silicate |
| Crystallography: | Cubic, rhombic dodecahedron, icsositetrahedron |
| Cleavage: | none, may show indistinct parting |
| Fracture: | conchoidal |
| Moh’s Hardness: | 70–7.5 |
| Density: | 3.84 (+/− .10) |
| Color: | light to dark purplish red through reddish purple |
| Transparency: | Transparent to opaque |
| Luster: | greasy to vitreous |
| Refractive Index: | 1.760 (+.010, −.020) |
| Birefringence: | none |
| Dispersion: | .026 |
| Pleochroism: | none |
