Tourmaline Facts and Buying GuideBy: Shweta Dhanuka Summary: It is the hard stone having the hardness of 7-7.5 Mohs and could be used for wearing daily in earrings, rings or pendants. However, in order to endure years of wear keep it away from steam cleaning, home ultrasonic cleaner and heating. It should also be protected from scratches and sharp blows.
Tourmaline, the name is derived from the Sinhalese word "tura mali," that
was referred as mixed assortment of colored gemstones. The name of this semi
precious gemstone is justified with its source name as it is found in many
different colours and in diverse colour combinations. This is the reason why
it is very close to the heart of people with the creative and artistic
instinct.
It is the gemstone for the August born person and wedding anniversary
stone for the couples in the 8th year of their marriage. Being a versatile
gem, no two gemstones are similar in appearance. The difference lies in
colour and facets of the stones. Therefore, while making the purchase of
this splendid gemstone, give time to see it under different light source.
Specific light sources are suitable for different colours. Read this and
more about the varied varieties along with common characteristics of
Tourmaline in the text below. It is written to make the buyers fully
acquaint with the diverse facts about the gemstone that would act as buying
guide. This would enable the buyers to make the purchase of actual gemstone
at the right price.
Colour -This gemstone occurs in all possible hues, tones and
shades of colours. The multiplicity of colour for this gem is not restricted
to the rainbow colours rather it is found in almost all the primary and
basic colours like shades of green, red, blue, yellow, brown, pink, black,
colourless etc. The colour disparities along the gemstone's length lead to
the bicolour and tricolour crystals that have whole host of colour
amalgamation. In simple words, bicolour tourmalines are those that display
two colours while tricolour display more than two colours in the same stone.
These varieties having colourful bands are quite fashionable. Combinations
of different colours in concentric circles and triangular patterns in one
single stone are also commonly seen like one colour at the center of the
stone while other colour around it.
This entrancing stone exhibits strongly the phenomena of Pleochroism.
Under it, the crystal is seen in diverse colours is diverse directions.
There is mix of dark, medium and light shades of the colour. Different
colour shades are seen along the vertical and horizontal axis. The maximum
dark colour shade is at all times observed from the bottom axis of the
crystal.
Varieties - On the basis of the colour this gemstone is classified
into ten varieties. Colour variations occur due to presence of different
mineral in the chemical composition in form of impurities. All the different
types are exclusive and special for the jewelry lovers. Sometimes the
jewelry designers create incomparable ornaments using all the colour
varieties in form of rainbow.
Watermelon Tourmaline - This is only one of its kind variety
having pink colour in the heart of the stone and green colour encircling
pink. It is the best example for colour variation in cross-section that
appears in concentric circles. Jewelry designers create fabulous ornaments
using it in a very unique way by setting it in slices instead of faceted
stones so as to boaster the incredible phenomenon.
Paraiba Tourmalines - It is a stone blue to bluish green in
colour. Minute quantity of copper and a tad of gold are responsible for the
colour. In the year 1987, it was first mined in Paraiba State of Brazil and
so named accordingly. This variety is to a large extent in demand when found
in good quality. Gemstone lovers procure it as the lifetime asset.
Red Tourmalines - It is also called as Rubellite. Mineral
responsible for red shades is lithium. The colour of the stone varies from
pale rose to deep ruby red with the minimum to maximum quantity of lithium
present in the composition respectively. Absolute deep ruby red shade is
very rare to be seen thus is very expensive. Finest quality is acquired from
Nigeria. A genuine high quality red colour stones shows same intense red
colour in incandescent light plus in daylight. Poor quality stones would
display brown hues in change of light source. It is believed to have
prominent sway on love and friendship, leading to permanence and firmness in
everlasting relations.
Blue Tourmalines - Across the world this variety is in high demand
but because of the limited supply it is not easily obtained. Nigeria is the
prime source for the best quality gems. Indicolite and Indigolite are
additional names for this variety. The originality of this colour could be
judged in daylight. It is alleged to radiate high grade of concord and the
wearer is trusted to experience frankness and patience. It could be seen in
different shades blue, black and brown in triangular pattern.
Yellow Tourmalines - It was first found in the mines of East
Africa. The gemstones acquired from Malawi in Africa possess brilliant
clarity thus are named as 'Canary'. The pure yellow colour without the
traces of any other colour appears due to the fine quantity of magnesium in
the composition. Alas, every single stone is not intense and clear yellow in
colour. Therefore, the pale stones are treated with circa at 700 degree
Celsius to achieve the desired bright colour. Difference between original
and enhanced stone could be distinguished in incandescent light.
One matchless aspect of this colour variety is that it can be
distinguished with its excellent fragrance. Malawi canary or yellow
tourmalines as rough are covered with black coating when it is obtained from
the mines. The first step of processing for this variety is to separate the
stone from the unwanted black material. So the roughs are boiled in the
mixture of water and lemon juice. As a result the black material is removed
and the stones exhibit dazzling lemon yellow colour with fantastic aroma.
Green Tourmaline - It is gaining popularity at the rapid pace.
Fortunately with good supply it is sort of affordable. As pink gem suits
females, green is for males as it endorses male stability and safety. It is
also called as Verdelite or Elbaite. Green colour is due to the presence of
chromium mineral in the composition. This stone is best observed in
daylight.
Black Tourmalines : It is the iron-rich variety hence is black to
bluish-black to deep brown in colour. It is said to defend the wearer
against pessimism. Schorl is it's additional name. Commonly used for
engravings and in esotericism as it is believed to protect its wearer
against detrimental waves.
Pink Tourmaline - It is available widely thus is reasonably
priced. It is more apposite for females as it encourages female balance and
security.
Colourless Tourmaline : As the name specifies it is having no colour. It is
called as Achroite and is rare in nature.
Brown Tourmaline - It is further more rare than the colorless
variety. It is also called as Buergerite and Dravite. These varieties are
not very popular.
Clarity - This fabulous gemstone is found in large crystals as
rough. Absolutely crystal clear gems are rarely obtained. The majority
inclusions in tourmaline are fractures and liquid-filled healed fractures.
In some stones needle like inclusions are also seen. However, clarity varies
from one stone to other with respect to its colour. For example - Blue and
green coloured gems consists less inclusions than red and pink stones.
Moreover, the commonly occurring inclusions could be removed with efficient
cutting. Minute fine and soft inclusions are sometimes appreciated and do
not affect the price.
Cut - It can be cut into any shape and size. However, it is not
that simple for the cutter. For this multi-colored gemstone cutters need to
use his/her skills at the optimum level to identify the right angle and side
of cutting so as to maximize the effect of Pleochroism. In order to enhance
the main colour, it is suggested to check the colour spots from all the
directions before cutting. The final look of the gemstone is totally in the
hands of cutter.
Dark colored gems are cut in a way that exhibits two lighter pleochroic
colours. Such stones have c-axis cut in parallel to the outer facet.
Similarly, light colored stones are cut to highlight the pleochroic deeper
shades. To achieve this, light shades are cut having c-axis perpendicular to
the outer facet. The phenomenon of Pleochroism is best seen in long
rectangular shapes. Also due to long and narrow crystal shapes of the
gemstone, rectangular cut is best to view the real beauty of the gem. Some
stones displaying cats-eye effect are cut into a cabochon as in this cut the
upshot is boosted. Emerald and oval cuts are next in the list of preference.
Rounds, triangles and trillions cut are followed then after.
Carat weight - Different varieties are found in different carat weight.
Paraiba gems are found maximum to 2 carat weight. More than this weight, the
crystals are considered as gems only for royal families. Red, blue and green
gems could be found between 3-5 ctw and beyond 10 ctw is rare and too
costly. Yellow gems could be procured between 1-3 ctw. Rest others tend to
be less than 3 ctw.
Price - This stunning gemstone could be an affordable gem as well
as an expensive buy too. It all depends on the colour varieties and their
respective quality and supply. Paraiba tourmalines are the priced maximum
then follows blue, green, red and watermelon gems. Intensity, rarity and
clarity of these varieties further affect the price. Final price is
ascertained on the basis of the carat weight. With every increase in the
carat weight of the gemstone the equivalent price increases.
Occurrence - This gemstone is amongst the most complicated
silicate mineral. Being a complex silicate of Aluminum and Boron, its
chemical composition varies with the presence of varied minerals like
sodium, calcium, iron, magnesium, lithium and many more. Granite & granite
pegmatite igneous rocks and marble, sandstone & schist metamorphic rocks are
the rocks where tourmaline occurs. Lithium-rich stones and Magnesium-rich
stones occur in igneous and metamorphic rocks respectively. It has the
Trigonal crystal system thus has three sides. It is found as long, thin to
broad prismatic and columnar crystals that are habitually triangular in
cross-section.
Source - It is mined through out in the world. Minas Gerais and
Bahia at Brazil are the prime source for all the varieties. Kenya,
Madagascar, Mozambique, Mexico, Myanmar, Namibia, Nigeria, Afghanistan,
Pakistan, Russia and Sri Lanka are few more countries that produce good
amount of this gemstone. Fascinating green and lovely pink colored gemstones
are procured from California, Utah and Maine State of United States of
America respectively. Tanzania is rich source of chrome variety green
colour.
Enhancement - A small number of pale stones are heat treated to
improve its colour. Some are irradiated to enhance the overall look of the
stone. Sporadically it is oiled to bury the apparent inclusions and other
surface-reaching cracks.
Imitations - It is yet to be synthesized by modern methods and
techniques. However, man-made imitations such as glass are frequently seen
in the gemstone trade market. Also poor quality natural stones are treated
to look like different varieties of tourmalines. All these and more are sold
under fancy trade names to dupe the innocent buyers.
Uses - This fascinating gemstone is used for creating attractive
jewelry items. Using the creative mix of varied colours of gemstone, jewelry
designer produce alluring designs. Rings, earrings, pendants, broaches,
back-pins, necklaces etc are created to suit the casual as well as formal
attire. All jewelries are made in 14K or 18K yellow gold/white gold.
Sterling silver is also widely used for making the stylish jewelry. Other
than the jewelries, it used as an ornamental stone. Figures and carvings
made up of this gemstone are popular in every corner of the globe.
Apart from these usual gemstones use, it is an important component in
making pressure gauges, specialist microphones and electronic
instrumentation. It is highly thought of by the scientist as it confers the
thermal and fluid history of rocks where it is formed. Also is closely
allied with several foremost metallic ore deposits, preserves chemical marks
of it's rock sources, succumbs isotopic proof for the environmental supply
of the boron and is a significant link in the boron cycle. One of its
unusual physical characteristics is that by heating or rubbing vigorously it
gets charged. Then it shows positive charge at one end while negative at the
other end. This is termed "pyro-electricity". Due to this feature it is used
to extract the ashes and dust from the pipes (Pipes used for smoking) and
named as "Aschetrekker".
Precautions - It is the hard stone having the hardness of 7-7.5
Mohs and could be used for wearing daily in earrings, rings or pendants.
However, in order to endure years of wear keep it away from steam cleaning,
home ultrasonic cleaner and heating. It should also be protected from
scratches and sharp blows. Large temperature change is hazardous for the
long-term life of the stone thus, must be avoided. Exposure to sweltering
sunlight, excessive heat, acids and harsh chemical present in cosmetics and
cleaning agents must be sternly avoided else the stones are ruined badly.
These few precautions and care would enable the forever the brightness and
glow of the gemstone.
Beliefs - In ancient time, many royal families used it in their
royal jewels like Russian Crown from the 17th century had red tourmalines
instead of ruby and the last Empress of China, Empress Dowager Tz'uHsi
adored pink tourmaline. She had an enormous collection of this startling
gemstone.
It is believed to shield the wearer in opposition to many adverse
circumstances and bad luck. It inculcates the positive traits like
confidence, enthusiasm, constructive thinking etc. and overcomes the
negativity. It creates the balance between different energies. It is trusted
to be idyllic for relationships as it fosters potent sway on love and
friendship resulting in immovability and constancy.
This awe-inspiring gemstone is treasured for its multi-coloured look. The
inimitable gamut of colours and plechorism flaunted by the stone makes it
very special for the gemstone collectors and admirers in the entire
universe. The soothing colours of the gem offer elegance and classy touch to
the looks of the lady. This rainbow gemstone suits all moods and surely
would fill as many its colours in your life.
Tourmaline Properties
|
Chemical Composition |
It is Complex Aluminium
Borosilicate and the chemical formula is (Na,Ca)(Mg,Li,Al,Fe2+)3Al6B3Si6(OH)4. |
|
Colours |
Green, red, blue, yellow,
brown, pink, black, colourless etc. Also bi-colours found like
amazing watermelon. |
|
Streak |
Colourless. |
|
Hardness |
7 - 7.5 Mohs. |
|
Luster |
Vitreous |
|
Refractive Index |
1.616 - 1.652 |
|
Specific Gravity
|
3.03- 3.25 |
|
Solid State |
Transparent to opaque. |
|
Crystal System
|
Trigonal crystal system. |
|
Fractures |
Sub-conchoidal to uneven. |
|
Cleavage |
Good to poor prismatic. |
|
Birefringence |
Medium. Varies between
0.014 to 0.021 |
|
Dispersion |
Medium (.017) |
|
Pleochroism |
Strong |
|
Tenacity |
Brittle. |
|
Source |
Brazil, USA, Tanzania,
Kenya, Madagascar, Mozambique, Mexico, Myanmar, Namibia, Nigeria,
Afghanistan, Pakistan, Russia and Sri Lanka. |
|
Enhancement |
Often enhanced through
heat treatments, irradiation and oiling. |
|
Precautions |
All general gemstone care
and precautions. |
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