Tourmaline Gemstone
Tourmaline frequently found in anthracite coal like black columnar crystals and scattered inclusions in granite is more popularly loved for dazzling displays of primary colour from deep red hues and mellow lemon yellow to rarer electric blue, vibrant green and ranges of every tone in between.
Tourmaline refers to a gemstone group that belongs to a type of silicate mineral family, with members sharing a repeating circular hexagonal ring structure of fantastically varied interchangeable elements.
From the most common darker “schorl” gemstone to deep coloured Hungarian “dravite” and scientifically important “Elbaite”, the family of tourmaline gemstone is one of the most extensive of all minerals.
Found widely across Brazil and Africa and with lesser commercially important sources in Asia, tourmaline has been described as a magnet for volcanic ash, used as a polarising filter for important scientific pursuit and well known for fabulous water melon dual colour varieties.
Loved for radiant colour since it was first discovered before the modern age, tourmaline has been selectively imported into China by previous Emperors and was found in ancient Indian burial sites as an offering for the ancestors.
A Family of Tourmaline Gemstone
Sharing a common six sided ring of repeating elements the tourmaline gemstone family group is described as one of most complex and largest families of silicate minerals.
In common with quartz and most of the minerals of the Earth tourmaline is a crystal whose principal connecting units are atoms of silicon connecting to four neighbouring atoms in a repeating lattice.
Less common is the complexity of the natural structure with numerous boron and aluminium atoms forming interconnecting and substitutable links in a dimensionally complex structure that is found on Earth in many different varieties.
Though sharing a similar spatial arrangement of atoms, tourmaline family members differ most strikingly in ranges of colour that vary from as black as coal to as vibrant as electric neon light.
Named from the German Saxony village from near where it was first recorded “Schorl” presents coal like blackness and texturing in the way it forms and is rich in sodium and iron trace elements.
“Schorl” was discovered before the 1400’s and today is recognised as the most common variety of tourmaline – found in small amounts in many metamorphic and igneous rocks such as granite as an accessory mineral.
“Dravite” rich in magnesium and sodium is a tourmaline family member recorded in the early 1800’s in Slovenia and named after a local river, with colouring rich in emotionally deep golden brown and dark forest green.
“Elbaite” is a lithium rich tourmaline gemstone and was the first mineral within which elemental lithium was discovered, named after the Elba island in Italy it has colourless transparent types to lighter natural colour varieties including strawberry pink, rare electric blue, red green and other primary colours, and is also famous for watermelon crystal bicolour tourmaline.
Prized by collectors of gemstones for it’s propensity to form large crystals, the tourmaline member “Uvite” is also known as “Flour-uvite” due to the presence of the element fluorite which gifts this gemstone rich reddy brown colours, though other tones are also found in nature.
There exist in total 32 family members of the tourmaline gemstone group found widely across the world, often in mineral inclusions as part of other rocks where the right makeup of diverse constituting elements leads to many more rare types of tourmaline gemstone.
With so many family members tourmaline is usually sold simply according it’s colour and not according to chemical differences, names from canary yellow tourmaline to red and blue tourmaline are more typically found.
The Formation of Tourmaline
Tourmaline is found around the world in igneous rocks such as granite, where it is scattered throughout the rock as a minor mineral inclusion.
As a commercially viable crystal tourmaline is extracted from the similar rock “pegmatite“, which is an important source of many other gemstones.
Pegmatite though similar in composition to granite is distinguished by a different process of metamorphic change, that results in the parent rock being a composite of large well separated crystals sometimes reaching massive sizes.
Gemstones including aquamarine, beryl and tourmaline among many others are found in pegmatite rocks as well as important commercial elements including lithium and rare earth minerals.
In the complex rich mineral environment at the high temperatures and pressures of geological process tourmaline gemstone crystals form into rocks and cavities sometimes exceeding several tens of centimetres in size.
Tourmaline is known for forming long trigonal crystals with curving striation, heavy faces and easily distinguishable by three sided faces that are not found in other gemstones.
Tourmaline gemstone is most famous for a wide variety of colour across the rainbow of the visible light spectrum that in nature will sometimes display two pronounced tones across the breadth of a single crystal.
The kaleidoscope of colours is believed to arise from differences in tourmaline’s chemical makeup that encompass many variations of different elements across family members.
“Schorl” crystals rich in iron display deeper bands of colours while “Dravite” varieties including magnesium cover dark shades of gold and brown, lithium containing “Elbaite” tourmaline cover most colours including transparent crystal finds.
Other coloured varieties include natural radiated pinks where deep underground radiation alters manganese varieties of tourmaline producing deep pink and rich red colours.
In the long process of tourmaline crystal growth the environment of the crystal will sometimes change just slightly enough to alter the colour of the crystal during formation.
Many tourmaline “water melon” crystals are found to vary from green to pink from one end to the next or from the outside to the interior and are a popular faceted gemstone showcasing the best of bicolour gemstones.
Tourmaline and the World
Tourmaline at approximately the same hardness of quartz on the moh’s scale is a durable mineral that persists through weathering that wears away most surface rocks and can naturally accumulate in river and alluvial flows where it is later sieved out of sediment by gemstone collectors.
Many beautiful gemstones of slightly rounded rough stone are found in the downstream rivers of Tanzania with Africa being one of the more important modern producers of colourful tourmaline gemstones.
Though used since ancient ages by Mediterranean peoples where it was locally found, tourmaline was first identified as a unique mineral by the Dutch in 1703 who imported the colourful stone from Sri Lanka and named it “turamali” from the Sinhalese for “multi colour stone”
Some of the early discoveries of tourmaline where made in North America Maine and California by native American people who used the rainbow coloured gemstones as offerings to ancestors, later 18th century development and commercial marketing of these localities produced the world’s most sought after green and pink varieties in the latter 19th century.
Chinese Empress dowager “Ci Xi” had a special fondness for the lighter colours of pink gemstone and imported significant quantities to be used as carvings and faceted gemstones that decorated grand summer palaces and adorned the social elite.
The modern world’s love of this natural rainbow gemstone has seen commercial sources opened up further from Indian to Sri Lanka and Africa, though the most notable finds come from Brazil.
“Paraiba” tourmaline is a colourful variety found in Brazil and is exported widely, the largest find of Paraiba tourmaline is a hefty two hundred carat gemstone named “The Paraiba Star of the Ocean Jewel” which is a flawless sapphire blue gemstone mounted in a colourful diamond encrusted yellow gold necklace.
Presentation of Tourmaline Gemstone
With a greater range of colour than any other gemstone tourmaline is the go to jewelry stone for lovers of vibrant colour and natural energy.
Rainbow colour is the hallmark of the lighter varieties of tourmaline gemstone such as “Elbaite” though darker coal black toned “Schorl” and golden brown “Dravite” varieties are more common.
Asides from radiant colours tourmaline has many other special properties including pleochroism and chatoyancy effects with pleochroism being found in most tourmaline varieties to different extents.
Pleochroism happens when rays of light passing through the crystal are changed with the path taken through it – observed as changes in colour when viewed from different directions.
Tourmaline gemstones vary in these colour changes quite significantly, red varieties will vary in intensity, green colours show changes in the amount of yellow and blue and brown types change from light to dark.
Faceted gemstones are cut to maximise the amount of colour projected from the setting, and the axis of the crystal displayed must be chosen carefully to minimise less desirable colour changes that result from the strong pleochroism of tourmaline.
Some tourmaline gemstone crystals including some of those from Brazil show great “chatoyancy”, where microscopic inclusions are oriented in a way that focuses light along an axis perpendicular to the inclusions, producing a bright band of reflected light known as a “cat’s eye”.
Tourmalines Special Properties
Along with beryl and opal, tourmaline gemstone is the modern US birthstone for October, sharing with these other gemstones a similar range of bright rainbow colour.
In the scientific world tourmalines greatest contribution to science was it’s use as a polarizing filter in 1678 by the Dutch scientist “Christiaan Huygens” in an experiment that was used to prove the wave theory of light.
Tourmaline is also known for a range of special properties including one which no other blue gemstone is known to produce.
Extensively analysed by the world of science in the 1900s minerals of the family member “elbaite” produced the first detectable traces of the element Lithium which now forms an important part of the modern low energy economy.
Tourmaline show interesting piezoelectric and pyroelectric effects with all crystals that lack a centre of symmetry accumulating electric charge when subject to mechanical stress or change in temperature.
Due to these special properties tourmaline was known as the “ash puller” gemstone and when heated was used to clean ash from smoking pipes due to it’s electrical charge attracting dust and soot – this effect also leads to tourmaline requiring more frequent cleaning than other gemstones.
Coal black “schorl” varieties that are heavily saturated with iron show strong magnetic response while “elbaite” varieties show different magnetic responses varying from red and green types with the lowest response to yellow, green and blue showing the highest.
Blue “indicolite” tourmaline shows the strongest paramagnetic response of any gemstone, though not generating a discernable magnetic field of it’s own it will however follow a neodymium magnet when it is placed next to one – being the only blue gemstone to do so.
Tourmaline Jewelry
Loved by jewellery artisans the rainbow of colour that tourmaline is found in is suited for all manner of design, from dark mysterious “schorl” to deep emotional “dranite” and the more popular kaleidoscope of lively tones that come from “elbaite” varieties.
Tourmaline is found in the market in a range of jewelry pieces from ear rings and rings featuring crystal cut faceted gemstones to pendants of single cabochons and bead necklaces and bracelets.
The colours of tourmaline are often enough to entirely carry the style of a design, some of our own designs are carried by the weight of radiance projected by the range of colours present in one bead of tourmaline.
“Water melon” tourmaline and other bicolour tourmaline crystals are an exception to the avoidance of buying bicolour crystals by gemstone buyers, with examples of faceted bicolour tourmaline crystals being found in a variety of beautiful jewelry types.
Many larger carat size faceted gemstones preserve the frequently found long elongated shape in specially designed settings.
Though “paraiba” gemstones that show radiant electric colour are some of the most sought after varieties of tourmaline, recent finds in Africa have similar radiant colours that are – with the exception of trace element analysis – indistinguishable from the Brazilian localities.
YAN Tourmaline Gemstone Fashion
Tourmaline is one of the craft maker’s most sought after gemstones, loved for the fascinating plethora of colour that can be used in an abundance of design.
Our own jewelry range use the natural colour range of tourmaline gemstones in evocative emotional pieces inspired by art, nature and our brand of new colourful styling that reaffirms beautiful design.
Matching ocean blue cordierite with the deeper emotional ranges of colour from selected natural tourmaline varieties our showcased matching set of cordierite blue necklace and bracelet projects eye catching beauty.
Lighter in colour and filled with colourful gaiety the rainbow tones of our silver bird pendant necklace is awash with colour from the principal tourmaline supported by the addition of light silver spacer and white quartz crystal supporting bead.
Natural deep purple amethyst colours match well to the lighter colourful gamut of tourmaline in the floral concept combination necklace that is further set off with additional silver flower brocade clasps.
YAN jewelry designs carry the vibrant colour of tourmaline in a range of attractive bead necklace and bracelet design where our designer has sought beautiful combinations of natural colour that carry the living vibrance of this popular gemstone.