During the late 19th century, a remarkable discovery of bright pink to pale violet garnets in Macon County, North Carolina, USA, caused a stir amongst gemologists and mineralogists. These experts quickly identified that these particular garnets possessed a unique composition of approximately one-third almandine and two-thirds pyrope content, making them distinct from previously known pyropes, particularly from Bohemia, and almandines from various deposits such as the European Alps or India. The unprecedented colour and composition of these garnets prompted the suggestion of a new variety name, RHODOLITE, derived from the Greek words "rhodos" meaning rose and "lithos" meaning stone. The name RHODOLITE has since been established as the trade name for this extraordinary gemstone.

Rhodolites are highly prized for their stunning range of purple hues, which can range from reddish-pink to red-violet and even display blue-violet shades. Furthermore, these gemstones exhibit an exceptional brilliance, owed to their high refractive index comparable to that of ruby, and boast a remarkable hardness and resistance to chemical reagents.

Rhodolites - like all gemstones of the garnet group - are not subjected to any treatment to artificially improve their properties.

Rhodolites are very interesting gemstones not only commercially, but also from a gemmological point of view:

In an extensive study, LIND et al. (1998) examined the absorption spectra of rhodolites and were able to explain the colours of rhodolites from different localities with the help of three different spectral types:

Rhodolites from Naktamunda, Orissa in India have a unique quality of being very clear and transparent in the blue-violet and red parts of the color spectrum. This gives these rhodolites a special blue-violet purple color that is highly regarded in the gemstone and jewelry industry. They were known as "Naktamunda rhodolites", but have disappeared from the market. The intensely blue-violet stones from Mozambique, which are often sold under the name "Purple Garnet" or "Royal Purple" can be assigned to the same type.

Rhodolites from the Arusha region in Tanzania have different colour characteristics compared to those from Naktamunda. These rhodolites show a lower transparency in the blue-violet part of the colour spectrum. As a result, they appear more purple with a stronger red component. The colour of these rhodolites ranges from a warm "wine red" to a "raspberry color" and is typical for several occurrences in Tanzania.

Rhodolites from Kangala, Tanzania are a third type. The spectra of these rhodolites show absorption bands which can be attributed to manganese and chromium or vanadium, in addition to the iron bands present in the other rhodolite types. This gives them a brilliant purple color that is highly valued in the gemstone and jewelry industry, and they are known as "Kangala rhodolites".

Depending on their actual chemical composition, some of the Rhodolites of the Kangala type may show pink-orange-red colours, while others can change from a purple-red when viewed under incandescent light to a greenish-blue colour when viewed under daylight. These stones can be considered to be in between "Malaya garnets" and color-changing garnets. These stones have found their own market niche within the community of gemstone connoisseurs and enthusiasts.

Investigations of rhodolites from deposits that have since then entered the gemstone market, e.g. from Malawi, have confirmed this classification.