Tourmaline is a virtual miracle of colours. It comes not only in
green and red, colourless and black, or as multi-coloured or
colour-changing precious stone or as chattoyant stone. There exist
besides uncountable mixed colours in all imaginable shades and depth,
even very unusual colours occur in Tourmalines. However, until
recently there was one striking gap in the sheer endless range of
colours displayed by the "rainbow gemstone”: the pure yellow shades
were missing. Most of the yellow Tourmalines found up to now show a
slightly brownish tinge. But Tourmaline not only comes in many
colours, it is also always full of surprises - like at the beginning
of the 90s, when suddenly there appeared on the market fantastic
bluish-green to turquoise-coloured Tourmalines from the Paraiba
mines in Brazil.
In the meantime the most colourful gemstone in the World has managed
to surprise us all yet again with another colour variation, and this
time it was the long-missed yellow. In the south of East Africa , in
Malawi, gemstone occurrences containing beautiful yellow stones were
discovered in the autumn of the year 2000. Their fresh colour
reminds of springtime, and these Tourmalines are clear and pure and
show just the finest greenish hue. Named "Canary”, the new
Tourmaline variety is already being offered in the market.
These gemstones are a very intriguing variation of Tourmaline. The
almost electric yellow colour is caused by fine traces of magnesium.
Since not all rough crystals show the brilliant yellow on being
found, some of the stones will have to be treated at circa 700
degrees Celsius in an oven before they can be cut. Failing such
treatment, the colour would keep a brown undertone. The
beauty-treatment can only be successful anyway, because it is
typical for Tourmalines to show different colours and different
satiation respectively when viewed from different perspectives. The
heating in such cases simply turns the second colour, a slight brown,
into the coveted bright yellow. This kind of treatment is frequently
applied to many kinds of gemstones, and the results are always
Larger yellow Tourmalines, however, rarely occur even in Malawi;
after all, only about 10 per cent of all the mined stones are
suitable for jewellery. When cut, over 95 per cent of the harvest
will weigh less than one carat. But nevertheless, they are
excellently suited for wearing, since like all Tourmalines the
canary-yellow beauties from Malawi achieve the good hardness of 7 to
7.5 on the Mohs’ scale.
There is another special characteristic feature which sets these
stones apart from the others: and that is their fine scent. It will
not be registered by the wearers, but by the cutter who gives the
gems their final shape with a steady hand, using all his skill and
expertise to bring out the fresh yellow colour as best possible.
Experienced cutters love working with these stones: " These are the
only gemstones which smell nice."
Why does a gemstone have a scent? The explanation is, in fact, quite
simple. On the place of their occurrence, Tourmaline crystals are
often embedded into black material, which will of course have to be
removed before the stones are cut. One day one of the owners of a
Malawi gemstone mine found out that the obnoxious black matter was
easily removed if you boil the rough crystals in water to which you
add some lemon juice. And ever since then the yellow Tourmalines
from Malawi not only resemble fresh lemons in their pleasant colour,
but also in their fine scent – at least until they have been cut.