According to an ancient Egyptian legend this is the result of the fact that
on the long way from the Earth's heart up towards the sun, Tourmaline
travelled along a rainbow. And on its way it collected all the colors of the
rainbow. This is why nowadays it is called the "Rainbow gemstone".
Tourmaline is a group of minerals comprised of a complex boron-aluminum
silicate with one or more of the following: magnesium, sodium, lithium,
iron, potassium or other metals. It appears in light from dark red to purple
as well as brownish variations of these hues - light to dark green,
yellowish-green, greenish-yellow, brownish-orange. It also grows
bi-coloured.
Varieties - Bi-colored, watermelon, cat's eye, alexandrite-like (rare).
Sources - Sri Lanka, Brazil, USA (California, Maine), Madagascar, Tanzania,
Kenya, Russia, Afghanistan, Pakistan (prime new source).
History - Dutch children played with tourmaline because of its ability to
attract light objects. The stones were called "aschentrekkers" (ash
drawers).
Cut and Uses - Any cut may be used. Some are carved, some fashioned into
beads. Cat's eye are always cut en cabochon. Sometimes carved to make use of
more than one colour.
However, the name "Tourmaline" has been derived from the Singhalese
expression "tura mali", which translates as "stone of mixed colors." The
very name already refers to the unique spectrum of colors displayed by this
gemstone, which is second to none in the realm of precious stones.
Tourmalines are red and green, range from blue to yellow. Often they show
two or more colors and are cherished for this parti- or multi-coloured
appearance. There are Tourmalines which change their colour from daylight to
artificial light, others display chattoyance. No Tourmaline exactly
resembles another one: this gemstone shows many faces and is thus
excellently suited to match all moods and tempers. It does not come as a
surprise, then, that ever since ancient days it has been attributed with
magical powers. Tourmaline is supposed to be an especially powerful
influence on love and friendship, lending them permanence and stability.
In order to understand this multitude of colors you will have to polish up
your knowledge of gemmology: Tourmalines are mixed crystals of complex
aluminium-borosilicate varying in their composition. The slightest changes
in composition will result in completely different colours. In fact,
crystals showing one colour only are quite rare; generally one and the same
crystal displays several shades and colours. Not only the wide range of
colours characterises this gemstone, it also shows a remarkable dichroism.
Depending on the angle of view the colour will be different or at least show
different intensity. The deepest colour always appears along the main axis,
a fact that the gemstone cutter has to keep in mind when cutting the stone.
This gemstone is excellently suited for wearing and is uncomplicated to care
for, since all Tourmalines show a hardness of 7 to 7.5 on the Mohs' scale.
Thus Tourmaline is an interesting gemstone in many aspects indeed.
Tourmaline seems to have a special place in the hearts of mineral collectors
as well as in that of gem and gemstone enthusiasts. Its nearly universal
popularity is based on two very important facts: first, it is a bright and
beautiful gemstone that can be found in just about any color; and second,
materials that are of acceptable quality are affordable to most purchasers.
The word "rainbow" is used figuratively to describe tourmaline. In reality,
it is a well recognized fact that tourmaline's diversity in color is not
limited to the seven colors of the rainbow. Tourmaline can be colorless to
just about any color, hue, or tone known to man. And if range of colors
among different tourmalines is not enough, individual crystals can vary in
color along their length or in cross-section. The variations in color along
a crystal's length give rise to the bicolor and tricolor tourmalines which
have multitudes of color combinations. The variation in color in
cross-section can be concentric, as in the case of "watermelon" tourmaline,
a pink core surrounded by a green rind. Or the variation may have a distinct
triangular pattern as in the case of liddicoatite. The four most common and
well known tourmalines are distinguished by their color and transparencies.
Elbaite is the gemstone tourmaline and comes in many varied and beautiful
colors. It is transparent to translucent and is highly prized as minerals
specimens and as gemstones. Elbaite is easily the most colorful of all the
gemstones.
The iron rich schorl is the most abundant tourmaline and is black and
opaque. It is a common accessory mineral in igneous and metamorphic rocks
and can form nice crystals. Although too opaque to be used as a gemstone,
schorl is used as an ornamental stone when found as inclusions in quartz, a
stone is called "tourmalinated quartz". Usually when someone refers to
tourmaline they are referring to either elbaite or schorl.
The main suppliers of tourmalines are Madagascar, North America, Brazil,
Myanmar (Burma), Africa, Siberia, Australia, Sri Lanka (Ceylon). Tourmaline
and opal are the birthstones of the month of October. Tourmaline is the
national gemstone of the United States.
Tourmaline has a wide variety of colors. Usually, iron-rich tourmalines are
black to bluish-black to deep brown, while magnesium-rich varieties are
brown to yellow, and lithium-rich tourmalines are practically any color:
blue, green, red, yellow, pink etc. Rarely, it is colourless. Bi-colored and
multicoloured crystals are relatively common, reflecting variations of fluid
chemistry during crystalisation. Crystals may be green at one end and pink
at the other, or green on the outside and pink inside: this type is called
watermelon tourmaline. Some forms of tourmaline are dichroic, in that they
appear to change color when viewed from different directions.
The most common variety of tourmaline is schorl, first described by
Mathesius in 1524. It may account for 95% or more of all tourmaline in
nature. The word tourmaline is a corruption of the Sinhalese word turamali,
meaning "stone attracting ash" (a reference to its pyroelectric properties).
The meaning of the word "schorl" is a mystery, but it may be a Scandinavian
word.
Tourmaline is used in jewelry, pressure gauges, and specialist microphones.
In jewellery, blue indicolite is the most expensive, followed by green
verdelite and pink rubellite. Ironically the rarest variety, colourless
achroite, is not appreciated and is the least expensive of the transparent
tourmalines.
Tourmaline is a very special stone indeed and holds an outstanding position
in the fascinating world of gemstones. Its excellent availability and unique
splendour of colours make it one of the most popular gemstones - and besides
almost every Tourmaline is an original.
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