Spessartine

History
Spessartine was named after the low Spessart mountain range in southern Germany’s Bavaria, where it was initially found in the township of Schaffenburg during the mid 1800s. The first gem material originated from the Rutherford and Morehead mines in the US state of Virginia.
Production from various locations around the world was always rather sporadic, which meant this garnet was never mass marketed. Moreover, although it appeared in attractive yellow and orange hues, they were always marred by a brownish tint, to the extent that spessartine most often displayed a dominant brown colour.
It was not until a deposit was discovered in the rugged mountains of north-western Namibia in 1991 that spessartine worthy of its name was unearthed in a colour never before seen in garnets, a brilliant fiery orange. Those beautiful ‘Mandarin’ specimens lacked any brown colouration. With a substantial supply assured, the stone soon became highly sought after in the jewellery trade.

 

Colour
Spessartine is an idiochromatic gem, that is, it is coloured by the major elements of its composition. Manganese is the key colouring element, conferring it a basic orange colour. This hue is often modified by the presence of other trace elements, chiefly iron in this instance, which tends to add a reddish or brownish tint depending on its oxidation state: FeO or Fe2O3 and darkens the stone to a brownish colour. Spessartine therefore mostly occurs in brownish yellowish-orange, brownish orange, brown and orangey-red. It can be confused with the whisky-brown hessonite variety of grossularite garnet.

The much rarer Mandarin variety of spessartine displays a relatively pure, bright orange colour.

Gemmological Properties
Spessartine is commonly found blended with pyrope, producing shades of pink, red and yellowish orange. Malaya or Malaia garnet is the variety name given to them in the trade.
This association also accounts for the peculiar colour-change garnets that display a range of colours in daylight and incandescent light, with the exception of blue, which never appears as a dominant colour in daylight. Although this garnet can be mistaken for others in terms of colour and appearance, it is easily distinguished by virtue of its singular spectrum.
Like other garnets, this gem is not enhanced by heating or irradiation.

 

Mining Areas
Spessartine is found often in the company of other gems in various locations around the world as far apart as Sri Lanka, Madagascar, Brazil, Australia, Kenya, Tanzania, Mozambique, Zambia and Pakistan. The bright orange Mandarin variety, initially discovered in Namibia in 1991, has been found in Nigeria since 1994. Although another deposit came to light in 1999, Namibia’s production is sporadic. Spessartine is also found as a by-product in Madagascar and Brazil.
These days Nigeria appears to be the only reliable source of the rare Mandarin variety.