Exceptional Spessartine Garnets

Spessartine garnet from Burma and Nigeria (34 ct), arranged on the print out of the chemical analysis (EDxrF) of the Nigerian sample. the main peaks in the XRF-spectrum are due to the presence of manganese within their crystal structure. Photo: M.S. Krzemnicki, SSEF.

first published in Facette 21 (February 2014)

In 2013, the SSEF tested a number of very outstanding spessartine garnets. This manganese dominated member of the garnet group commonly shows a highly attractive and vivid orange colour and is thus also known and described in the trade as ‘Mandarin garnet’. These gems can also be found as stones of exceptional size and clarity. Furthermore, they do not undergo treatment (as there is no successful treatment known to date, except possibly fissure filling which could be applied for any fractured stone). We think that these factors add greatly to their attractiveness.

In the last few months, we had the pleasure of analysing not only a few outstanding spessartine garnets of up to 100 ct, but also a unique collection of 16 stones (total weight approximately 320 ct) of exceptional quality and highly matching vivid orange colour. The gems had been carefully pre-selected for future use as a jewellery set, consisting of a necklace, a pair of ear-pendants and a ring.

There are only very few gem deposits worldwide which have produced gem-quality spessartine. Three of them are located in Africa with the Kunene area in Namibia, Loliondo in northern Tanzania and the gem mines close to the village of Iseyin in western Nigeria. From these three sources, the deposit in Nigeria stands out as it has produced some of the largest and purest spessartines ever found, such as the ones described above. In addition to this, we had also the opportunity to investigate a number of spessartine garnets originating from Mogok (Myanmar). Our samples were provided by SilkenEast Co. Ltd. (Bangkok) and Yavorskky Ltd. (Bangkok) and showed a beautiful orange to slightly reddish-orange colour, due to a higher iron concentration. A number of these stones have been added to our SSEF reference collection that already contains samples from the other mentioned main sources of gem-quality spessartine.