Star Gemstones: Asterism in its Enticing Glory

Mankind has always been drawn to the mystical skies shinning with uncountable number of stars. Since time immemorial, numerous artworks have been inspired by the stars and planets twinkling. And when someday, gemstones with starry dazzle were discovered, it meant owning the stars. Meanwhile not all gemstones known to man exhibit the starry dazzle and it is an exclusive phenomenon. But why is that? That’s because, it is an optical property based on the crystal structure.

What is the phenomenon called?

The property is called asterism. Asterism is an optical phenomenon that occurs sparingly in some gemstones. When the light beam passes through the crystal, it showcases star-shaped figure. In astronomy, asterism is defined as a pattern of stars. It is very different from what we know as a constellation. Asterism is a pattern of stars or constellations which may not be recognised in any form.

Types of Asterism:

There are two distinct types of asterism exhibited by the gemstones found naturally. They are:

  • Epi-asterism:

Seen in sapphire gemstone and garnet beads, epi-asterism is caused due to the reflection of the light along the parallel planes formed from inclusions/ rutile within the gem crystal.

Garnet+beads

  • Di-asterism:

Commonly seen in the Rose Quartz, the phenomenon is seen when the light source is behind the stone. The phenomenon is seen in crystals with milky and opaque appearance.

In short, di-asterism in gemstone is caused by a transmitted light, while epi-asterism occurs due star formation from a reflected light beam. Diffused light sources don’t form star shapes in the gemstones.

Asterism in Sapphires:

The first instance of gemstone asterism was discovered by the Greeks. The cuts necessarily enhance the phenomenon. For example, star sapphires cut in cabochon display six-rayed star pattern. Other stones that exhibit the property are rubies, topaz, chrysoberyl and moonstone. The presence of titanium oxide particles, called rutile, gives the gemstones their trademark asterism.

Gemstones with asterism have always been linked to folklore and superstition. They were believed to ward off evils in the dark and keep the faith strong. Star Spinel, garnet, Diopside and sapphires were specifically cut to enhance the healing properties of the protective gemstones.

Asterism in Quartz:

Pink and red quartz exhibit asterism that occurs due to transmitted light. Citrines also reveal asterism when heated to a certain temperature. The heating dissolves the finely lined rutile particles an align them to form stars. Round cut quartz are known to showcase exciting play of star formation, with interesting planes.

Asterism in Synthetic gemstones:

Synthetic corundum is aluminium oxide which is largely produced to replace diamonds in cutting and abrasive tools. The asterism is seen in corundum gemstones.

spinel+gemstones

Commercial influence on Star gemstones:

Asterism is a key commercial feature that makes the gemstone look rarer in the market. Star beryl and star spinel gemstones are anyways rare, which are complemented with immaculate cuts and shapes. Star gemstones too have to meet the 3 C’s parameter to qualify as precious item: Colour, clarity and Carat.

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Paraiba Tourmaline: The Neon Gems from Amazonia

Tourmaline gemstones and Paraiba are now commercially accepted as synonymous with each other. Considered as an electrifying item for jewellery and fashion, tourmalines bearing this characteristic shade owe their origin to north-eastern parts of Brazil. Much later, the sizzling varieties in effervescent green-blue were mined from Mozambique and Nigeria. If you are planning to buy a Paraiba tourmaline, there are chances that you might get confused between the ones coming from Brazil and those mined from Africa.

tourmaline-gemstone-beads


How are they different? Does it really count if they are from different sources? How to tell the difference between the two?

In terms of physical differentiation, it is very hard to find the variation between the Paraiba tourmalines from Africa and Brazil. Even under the microscope, they are hard to be differentiated.

So, how to differentiate? The only way gem labs can find the difference is by using quantitative chemical testing. Origin-wise, gem collectors rank Brazilian tourmalines higher than the ones mined from Africa. The African tourmalines have a reputation similar to what Burmese rubies enjoy in the gem lines.

History of Paraiba:

One of the recently discovered naturally occurring gemstones, Paraiba tourmalines have a history dating back to 1980s, when Heitor Dimas Barbosa and his assistants dug out pegmatite deposits in the hilly areas of Paraiba in Brazil.

Why are Paraiba gemstones so popular?

The shady electrifying blue shade in the Paraiba tourmalines matches the beauty of blue sapphires. The blue colour appears due to the presence of copper oxides and hydroxides. Brazilian stones are darker in colour compared to their African counterparts by virtue of higher copper ions in the crystal structure.

Paraiba tourmalines exhibit a variety of colours ranging from sky blue to aquamarine to psychedelic blue. Highest variation in colour shades is observed in Mozambique Paraiba tourmalines.

World’s most famous Paraiba:

The Guinness World Records rank stunning Ethereal Carolna Divine Paraiba as the world’s largest, flawlessly cut naturally occurring Paraiba tourmaline in the world.  It weighs 191.87 carats and is enlisted in the same bracket as Logan Sapphire, Hope Diamond, The Golden Jubilee and Alan Caplan Ruby.
 
The Ethereal Carolina Divine Paraiba is an oval shaped tourmaline featuring Brilliant Cut, and is four times heavier than the second largest tourmaline ever mined. The stone now graces as a part in the necklace called Paraiba Star of Ocean. It entered the ranks in 2009 when the stone featured in the necklace designed by Canadian jewellery house- Kaufmann de Suisse.

blue+topaz+gemstones

This tourmaline exhibits a radiating neon blue-green colour very distinct from the traditionally mined stones. It is best described as the blue of the tropical ocean. Even the necklace it is fit into has been inspired from the aqua flora and fauna. A compliment to the marine animals like turtles, shells crabs, star fish, rays and sea horses, Paraiba tourmaline is flanked by the likes of canary yellow diamonds, blue, orange sapphires, ruby, garnet, emeralds, blue topaz gemstones and Tsavorite. The 191.87 carat Carolina tourmaline easily exceeds the size of all other gemstones.

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Rose Cut: A look at the Pristine Diamond cutting technology

Rose cuts are not new as they are often quoted to be. There have been instances when diamond dealers rate the rose cut as 20th-century phenomena. Breaking the norm, rose cut diamonds were pretty much the regular jewellery items in Antique and Heirloom collections. First rose cut diamond was made in the 16th century. This cut continues to win hearts and remains one of the most sought after stones in the modern jewellery sets.

Why are Rose Cut diamonds named so?

The diamonds are cut in the shape resembling the open petals of the rose with the spiralling pattern. When cut in the shape of the rose petals, the diamonds have a flat bottom and a larger surface area. This opens the surface to exhibit the brilliance even more emphatically. They feature triangular facets in the multiples of 6 on the tipped crown of the diamond.

Why rose cuts lost the charm?

Undoubtedly, the rose cut diamond were symbolic representation of the Moughal glory in India. One of the most popular medieval gemstones is the Great Mogul, owned by Shah Jehan. The French traveller and gem collector, Jean Baptiste Tavernier,as one of the most beautiful stones he has ever seen.

Between 18th and 19th century, rose cut diamond lost the position significantly. New machining tools and cutting saws rendered the rose cut diamonds as out of fashion. They were largely replaced by the Brilliant Cuts Diamond. The popularity of Table Cuts and Point Cuts in diamond gems made the floral shaped diamond stones all the more obsolete in the 18th century.The cut returned with a bang when the gem collectors tagged this as synonymous with the “engagement” and “romantic” stories.

What are different versions of rose cut?

Rose cuts are made on the diamond in an upside-down manner. The flat base is complemented by the dome-shaped crown converging at the centre of the stone. The different names of the Rose cut are Crowned Rose Cut, Full Holland Cut, Antwerp rose, Dutch Cut and the very popular Antwerp Rose cut diamond is machined in a hexagonal shape.

The Rose Cut Diamonds can be cut into 24 facets and 48 facets (called Double Dutch Rose). If you observe closely, the "Briolette Cut diamond" is actually a modified twofold Dutch Rose cut which has half of its hemisphere elongated against the other hemispherical half.

Another prominent variety of the cut is the Senaille Cut which has notable unsymmetrical facet.

Rose Cut Diamond Solitaire: The Magic

Considered as a regale cut, Rose Cut is used extensively in diamond solitaire, re-introduced with brilliant clarity and pristine lustre. The open mouth cut allowed the light to pass through the crystal freely with no hindrance in the setting.

Almost all diamonds can be cut into Rose. The most prominent factors to determine the feasibility of cutting a diamond into Rose are width and depth of the stone. Symmetry and crystal alignment are secondary factors that lapidary artists look for before going ahead with Rose Cut.

Colour changing Gemstones: The Mystery Decoded

There are exclusive gemstones named specifically as per the colour they reveal. For instance, Turquoise, aquamarine gemstone, opal, lapis gemstone and many more are only a handful of an exhaustive list. And then, there are others that have an effervescent optical characteristic of changing colours depending on the angle you view them, or on the way light falls on them.For example, Alexandrite runs a beaming green shade in daylight and mysteriously transforms into richly blue under fluorescent light.

Aquamarine+Gemstone+beads


If that is not enough, the same stone displays a majestic play of orange and red colour when exposed to incandescent light.

How distinct is colour change phenomenon in gemstones?

Colour change is a well-recognised optical phenomenon that occurs in a gemstone when exposed to different wavelength of light. This optical property is observed in sapphires and garnets too, but it is exclusively called “Alexandrite Effect”.

What is Alexandrite?

A type of chrysoberyl, Alexandrite is an orthorhombic gemstone named after the Tsar of Russian, Alexander II (1818-1881). Discovered for the first time in the Urals near River Tokovaya in 1834, the gemstone gained immense popularity only after master gemstone George Frederick Kunz produced some of the most magical platinum and diamond ensemble featuring Alexandrite.

What contributes to the Play of Colour?

The chemical composition complemented by the crystalline structure and its double refraction index of 0.009 gives the stone its majestic optical brilliance. Just like its optical phenomenon, the crystal itself so very rare in the nature. Alexandrite is not a regular chrysoberyl. In addition to iron and titanium oxides, the gemstone also contains traces of chromium. Some minor traces of vanadium and gallium are also present but they are considered as impurities, rather than featuring as colouring agents.

Due to the presence of so many ions, Alexandrite reveals a show of colour ranging from green to yellow, brownish red to purple, yellow green to bluish green.

The most genuine form of gemstones:

Alexandrite is rarest gemstone to make it to the collector’s list. They are mined from Sri Lanka, India, Madagascar, Zimbabwe, Burma, Tanzania and Brazil. Synthetic Alexandrites are yet to be produced with satisfying results. They remain untouched by the heat treatments and dyeing agents that mark the markets for sapphire and rubies.

Cats+eye+gemstone

A true gemstone bearing the tag of Alexandrite always exhibits two optical phenomena: Cat’s eye gemstone or chatoyancy and change of colour.

Cut and Clarity:

Alexandrite is blessed with clear lustre and rarely has any inclusions. It’s the inclusions in sparing numbers that give the gemstone its chatoyancy property. Often cut in mixed cuts, aristocrats prefer uncut Alexandrite owing to the rarity and save weight. They are mostly available in cut form weighing less than one carat.

However, some world-famous Alexandrite stones are actually way heavier than standards. For example, the 17.08 carat Whitney or the 43 Carat Gem or 66-Carat Gem… they all are big and magnificent.

Perfect engagement gifts revered by the lovers all over the world- The Alexandrite Russian rings set on platinum.

Roman Love: Sizzling Garnet Varieties

Garnet bracelets are one of the world’s oldest recognised forms of gemstone jewellery. The Romans were known to adorn the rings and crowns adorned with garnet gemstones of different sizes.  They continue to be as impressive as they used to be in the 15th century.

Garnet+gemstone+beads


Garnets look like Pomegranate grains!

Yes, they do resemble the fruity grains. And that is why they are named from Latin word “Garanatus” that translates to “like seeds of pomegranate”. Small garnets are brighter in shade than the bigger ones. If you have difficulty analysing the authenticity of the garnet, get it tested under a refractometer. There are many varieties of garnets. Some of the popular varieties are:

  • Pyrope
  • Almandine
  • Grossular hessonite/ tsavorite
  • Uvarovite
  • Andradite
  • Rhodolite
  • Spessartine

Here are some less common, but very precious garnets available in the market sparingly.

  • Goldmanite
  • Morimotoite
  • Katoite
  • Hibschite
  • Kimzeyite
  • Schorlomite
  • Majorite
  • Calderite
  • Hydro-grossular
  • Knorringite
  • Kimberlites


World of synthetic garnets:

Garnet is one of the easily synthesised gemstones in laboratories.  Apart from silica, calcium and magnesium, garnets crystals can be impregnated with ions of Germanium, Gallium, Aluminium, Vanadium and Iron.

Very similar to zirconium, garnets too have their own series of synthetic gemstone members. Yttrium aluminium garnet- YAG, is one of the most popular and commercially accepted garnets to have made it big in the market. Other significantly popular synthetic garnets are Yttrium iron garnet- YIG, and Gadolinium gallium garnet- GGG. All synthetic garnet beads are coated with a film of magnetic substrate to replicate the magneto-optical properties as seen in the real gems.

Garnet+beads


So, how to identify a real garnet?

Physical testing for hardness, colour, magnetic properties and abrasive nature are popular methods used to separate original garnets from the synthetic ones.

Colours of garnet:

Garnets used in modern day jewellery exhibit myriad colours like red, orange, yellow, green, purple, brown, blue, black, pink and burgundy. Some garnets are pale and colourless as well which can be coloured after heat treatment.

Darker the colour of the garnet, older is the age of the gemstone. Depending on the diffusion, garnets can have shallow colouring as well as core colouring.

Discovered in 1990s, there is a special family of garnet called Blue pyrope–spessartine garnets. They exhibit multiple colour hues when observed from different angles. The colour changes from shades of green to purple, depending on the diurnal temperature and natural slight intensity.

Hardness:

Garnets is one of the hardest naturally available material on the planet. The synthetic garnets have hardness measured in Mohs scale. They could be anywhere between 6.5 and 7.8.

Magnetic Properties:

Easily the most authentic method to detect original garnets, magnetic susceptibility to neodymium magnet is a common feature among end members of the series.

But hey! Like all gemstones, garnets too can be faked and forged with impressive adulation. That is why there are certain restrictive trade regulations to keep only original garnets in the market. Find and assess gemstone certification that is tagged on every garnet.

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The Story Behind the Irradiation of Gemstones

Different gemstones exhibit a varied reaction to different types of treatments. One of the most popularly used treatments to produce brilliant gemstone is the process of irradiation. Light blue topaz gemstone turns into dark brown after radiation. The same brown topaz gemstone is reversed to its original blue colour by exposing it to a controlled heat treatment under specific conditions of temperature, pressure and catalysts.

Blue Topaz Gemstones


What is irradiation?

Irradiation is just a miniature controlled nuclear attack on the gemstones. Imagine the crystal structure as the target, and a series of gamma ray bombs hit specific spots inside the gemstone. The bombardment of the gamma rays alters the colour of the gemstone significantly, without actually making little or no difference to other physical aspects like hardness or density.

Irradiation can lead to both addition and removal of certain ingredients in the structure leading to change in hue. There are certain colour centres within the crystal structure that give different shades when bombarded with gamma rays. That is why irradiation of gemstones is achieved not by trial and error, but using specific nuclear kits.

Does irradiation cause any kind of damage to the precious gemstone?

Basically, the process of irradiation is a great way to produce brilliant gemstones from rather disappointingly dull stones using no physical force. When the gamma rays hit the colour centres within the crystal structure, the cells are knocked out in a random motion. The systematic process of irradiation can produce brilliant colours which are permanently restored and made more attractive by exposing the stone to heat and pressure.

Is irradiation a permanent process?

The fact that gemstones irradiated using gamma rays are produced under intense temperature makes them a permanent item to wear. The colour is long sustaining and can possibly be reversed to its original shade by applying an equally high bounty of energy. It is certainly an irreversible colour transformation process as far as irradiated gemstones like topaz are concerned.

Is irradiation a costly affair?

Of course it is! Otherwise, all the blue topaz available in the market would look like brown speckled stones with absolutely no commercial viability. Almost 95 percent of the blue topaz are irradiated and treated with heat before they get their signature shade.

Irradiation is done using highly powerful nuclear bombardment machines that cost millions. Only organizations having certificate to operate a nuclear machine can use it. Moreover, it requires skilled gemologists and operators who understand both aspects of gemstone properties and nuclear physics.

Thus, the cost of irradiation of gemstone is a pricey affair. But it ensures that the end consumers get only high quality gemstone produced from natural extracts and polished by skilled professionals.

Are there certificates to tag irradiated stones?

Yes, there are different certifications offered across all continents to ensure gem quality. It also ensures that none of the gemstones have turned radioactive. The major certifying units are GIA, AGS and other renowned gemstone research labs.

Apatite Gemstones: The Classical Underdog

Apatite is one of the most underestimated gemstones, considering the family it belongs to. A cool blue gemstone that derives its name from Greek word meaning “deceitful stone”, apatite is a misleading rock owing to its resemblance to other blue rocks like aquamarine beads, beryl, topaz gemstone and fluorite. Polishing and heat treatment with enhancing agents can make them deceivingly appear like sapphires and lapis lazuli.

aquamarine beads

Let us explore the gemstone, which is everything but not deceiving.

Beads of power:

Apatite gemstones are popular, only next to tourmaline. They have a hardness of 5 on Mohs scale, which makes them an easy candidate for cutting and shaping into desirable shapes. Clear cut apatite exhibit cat’s eye effect or chatoyant phenomena. Presence of rutile give it the exhilarating effect.

Extra-terrestrial stones:

Oh yes... apatite gemstones don’t have an earthly origin. They are believed to have been carried to Earth by meteors and comets that crashed onto the surface millions of years ago. The presence of apatite on many outer planets in fact signify the presence of water, much like what we have on earth!

In terms of astrophysics, apatite is definitely a high priced commodity to reckon with.

A dreamer’s stone:

For peaceful sleep, gem collectors embrace apatite as it is known to induce tranquillity. It also improves hunger and soothes the digestive system. For higher level of concentration and better balance in life, apatite beads and bracelets are embraced for a long lasting effect.

Apatite varieties:

Popular varieties of apatite are green apatite, Asparagus stone, neon blue-green apatite and samite apatite blends. Since, the gemstone market is full of heat treated apatite, it is usually considered safe to buy only light shaded rocks.

Impregnated by rare minerals:

One of the rarest forms of apatite are found in Hoidas Lake, Canada. The speciality of the apatite extracted from these areas is that it is loaded with rarest of the rare minerals like dysporium, allanite, tonalitic gneiss. In fact, apatite in this part of the world falls in the category of “rare earth mining project”.

Colours to die for:

Apart from the scintillating tropical blue green shade, apatite gemstones are also found in apple green and sea blue hues. The rare blue shade apatite is actually known as “Moroxite”, and is a high priced gemstone. It is often produced by heating the light coloured mineral.

 

apatite gemstones

Cuts and shapes:

Apart from the usually beads and rounded apatite, the gemstone is also cut into cabochon and placed in doublets and triplets for an enhanced brilliance. Chatoyant apatite gemstones are not treated artificially and often sold in high-class market at prices $ 150 and more per carat.

Life of the stone:

Despite its relative softness compared to other blue gemstones, Apatite can survive force and corrosive reactions. Pure untreated apatite are susceptible to bio-leaching where the constituents of the stone corrode away due to the action of micro-organisms.

However, there are many dimensions of apatite in the gemstone market that makes it a very good item to collect and adorn.

Impregnated gemstones: The World of Colourful and Flawless Rocks

Technology has made the world colourful. And we say this because of new-age gemstones making their legitimate entry into the market backed by stamp of purity, clarity and brilliance. Impregnated gemstones are flawless rocks with minimum tolerance for cracks, gaps and air bubbles. Porous gemstones are often heat treated in presence of doping agents and dyes to gain a superlative clarity and colour. A mix of chemical action and annealing gives impregnated gemstones their signature maturity.

Why do gemstones require enhancement?

Only 1 percent of natural gemstones meet the benchmark values of clarity, colour consistency and physical durability. Dealing in high priced gemstones makes enhancement process even more important.

Enhancement of gemstones is done to fill up cavities, define outlines of crystalline structure and make cutting relatively easy. Porous gemstones are hard to cut, and enhancement using resins and fillers render a degree of durability to the rocks after treatment.

Impregnation as a method of stabilization:

Impregnation turns a relatively porous gemstone into a durable item. Even the inexpensive rocks are then dyed and coloured to derive a good quality gemstone, exuding classical brilliance often displayed by traditionally precious gemstones.

Impregnated gemstones available in the market are:

They are first bleached and then impregnated to boost the clarity and shine. Dyed and impregnated jadeite are classified as D-Jade. The impregnated jades display higher refractive index, with sturdy crystalline structure.

Nephrite Gemstone


The treated jade are detected only under high magnification IR Spectroscope.

Hardened resins and beeswax are used as fillers in treating flawed turquoise. The trademark Zachary treatment is exclusive impregnation process that involves addition of chemical fillers to semi-precious stones and then heating them in an oven. Impregnated turquoise gains a sparkling colour with a hard-wearing structure that does not chip away during cutting and machining.

Turquoise Gemstone

  • Rubies and sapphires:

Lead glass filling is rapidly making an inroad into the mainstream gemstone market. Despite its notoriety as a hybrid process, rubies and sapphire gemstone with major flaws are increasingly added with lead glass fillers. The accepted percentage of impregnation is less than 30 percent.

  • Black onyx Gemstone:

A very popular coating process, black onyx derives its signature shade from the lacquer and silica polymer impregnation.

Techniques to identify impregnated gemstones:

  • IR Magnification:

Spotting and inclusions are visible under high magnification spectroscopy. The colour concentrations also vary for an impregnated gemstone.

  • UV Florescence:

Some fillers light up exhibiting florescence when exposed to rays which appear distinct from the host stone surface.

  • Heat zones:

Fillers and host gemstone structure have distinct heat zones when exposed to higher temperatures.

  • Odour test:

Gemstones impregnated with balsam and cedar oil exude a signature odour when exposed to high temperature. It is a ballpark method though.

Conclusive results are obtained through X-ray diffraction and Raman Spectroscopy, but they involve very high cost of operation.

All gemstone regulating organizations like GIA, AGTA and CIBJO ensure that consumers get quality gemstones, and not compromised rocks.

Highly Popular Gemstone Treatments & Enhancements

Only 1 percent of the naturally obtained gemstones are perfect and meet the textbook definition of “being flawless”. When it comes to turn the gemstones into acceptable items for the market, they have to undergo numerous processes ranging from cutting to polishing to dyeing and heat treatment. While some treatments involve only removal of the flawed parts, others include enhancements, doping and filling.

Here are highly popular gemstones treatments and enhancement processes done on diamonds, rubies, sapphires, garnets and almost every other rock known to mankind holding significant economic value.

Heat treatment:

Done incontrolled conditions, heat treatment of gemstone causes a drastic change in the colour. Rubies grow fiery red when exposed to heat. The untreated rubies and sapphires have gas bubbles and silk rutile inside them, which disappear after heating. In sapphires, heating in a flux of beryllium produces an electrifying blue shade.

Gemstones that are given heat treatment to improve clarity and brightness are:

 Blue Topaz Gemstone Beads


Oiling:

Done for natural emeralds, oiling is done to improve the clarity. Use of cedar oil is a universal process. Apart from clearing the surface of emeralds, cedar oil acts as a wonderful filler. The fracture filling done using cedar oil enhances the refractive index of emerald. Oiling is a temporary enhancement process owing to chances of leaching. An oiled emerald requires repeated treatment to look its best.
Oiling done using fillers and resins apply to alexandrite, rubies and chrysoberyl.

Irradiation:

Also called gamma-ray bombardment, this is a technologically advanced process that transforms the crystalline structure of the gemstone. Largely irreversible, irradiation of blue topaz is a symbolic example of what an irradiated gemstone looks like.

Quartz minerals are irradiated with Cobalt-60 to produce brilliant amethyst in versatile colours. Colourless beryl gemstones turn into brilliant golden hued beryls, also called helidor. A colourless beryl will fetch $100 per carat, but an irradiated gemstone from beryl family will fetch anywhere between $300 and $450 in the market.

Other popular gemstones treated with gamma radiations are:

  • Tourmaline
  • Diamonds
  • Pearls
  • Zircon
  • Fluorite

 Gamma irradiation is often followed by annealing to arrive at a consistent clarity and superior brilliance.

Aquamarine Beads

Colouring and Dyein:

There are many ways gemstones can be coloured. They are either stained, bleached or dyed with colouring agents. Dyeing is probably the oldest known colour enhancement process dating back to the days of Pharaohs. Stones are either soaked in dyes or heated in a colour agent to enhance the colour.

Staining, on the other hand, is done using a penetrative solution that enters the fault lines and cracks. Commonly, black onyx and pearls are coloured by staining and dyeing process.

Bleaching is a process where the colour is removed, and not added. It adds clarity and lustre to the white gemstones. Onyx, pearls and corals are bleached to gain uniform consistency.

Depending on the extent of processing and treatment, the cost of the gemstones may vary considerably.

Black Gemstones You Never Knew Existed!

Considered as the powerful shadows of the brilliant coloured gemstones, the Black Stones are no longer kept in oblivion. Much like their colourful siblings, black gemstones too have a respectable fan-following. There are many black gemstones used in jewellery and healing, but we present you a list of those featuring in almost every charmer’s wish list.

Black Gemstones


Black Diamond;

Heard about the 33.75-carat Amsterdam Diamond? Or the 312-odd carat the Spirit of de Grisogon! These are black gems.

Diamonds are available in almost every colour known to mankind. And yes, black is one of them. Though rare, black diamonds actually look like the other allotrope of carbon, the graphite. Black diamonds are actually called “Carbonado” and are tougher than the regular diamonds! It consists of traces of diamond, graphite and non-crystalline carbon.

Most geologists believe that carbonado diamonds are actually extra-terrestrialin nature dating back to 3.8 million years of space travel.For instance, Carbonado do Sergio has a meteoritic origin.

Black Opal:

A fascinating variety of opal, Black Opals earned so much popularity that New South Wales- Australia proclaimed it as the official state gemstone! NSW is the world’s largest producer of Black Opals. Due to the small traces of iron oxide and amorphous carbon, some opals exhibit a unique trail of black. Black Opal set in bezel ring is considered as a protection from the evil forces.


The Halley's Comet Opal, a 1982-carat Black Opal is world’s largest uncut gemstone, priced at $1.2 million.

Black Beryl:

Beryl is pretty common in nature, but when they appear in black forms they enter the list of rare gemstones. The black shade appears due to the insertion of microscopic black spinel impurities. They often appear as elongated prisms turning the transparent and clear beryl into greyish. The black opals are distinctly identified by their asterism effect, found in cabochon cuts.

Black Sapphire:

Sapphire is a legendary gemstone particularly recognised from its electrifying blue colour. But the black varieties are even more spectacular in their appearance. Symbolised as the stone of wisdom and confidence, Black Sapphire contains significant amount of aluminium oxide arranged in prismatic tubular and rhombohedral crystalline structure giving them their conspicuous star-shaped optical effect.

Black Sapphires are very well received in the Arabia and Roman culture as an embodiment of fertility and love.

Black Star of Queensland is a 733-carat black star-sapphire discovered accidentally in 1960 in Queensland, Australia.

Black Garnet:

Also known as Black Andradite, it is absolutely hard to imagine that a flourishing red gemstone will also appear in a metamorphic form in black colour! The black garnets are actually a combination of three distinct crystalline structures- pyrope, andradite and melanite. A deeply spiritual gemstone, Black Garnet exhibits clairvoyant properties and heals the negative energy circles.

Other prominent black gemstones in the family that are equally sparkling and popular are Black Obsidian, Smokey Quartz, Black Tourmaline, Onyx and Serendibite.

So next time you shop for gemstones, don’t forget to pay special attention to the black family.