A number of reputable laboratories are engaged in the certification of coloured gemstones. This includes the aforementioned GIA (Gemological Institute of America), the Swiss Gübelin Gem Lab (established in 1920) and the IGI (International Gemological Institute) which has offices in Antwerp, New York, Hong Kong, Mumbai, Bangkok, Tokyo, Tel Aviv and several other cities.

GSI (Gemological Science International) and AGS (American Gem Society) are also well known in the industry. The main criterion is that the laboratory should be independent and unrelated to the stones’ miners and sellers.

It is also important to know that the certificate of a reputable laboratory can be checked for authenticity. Most independent laboratories offer for you to check the certificate according to its serial number, on their website. 

While gemstones are strong, they do require varying levels of care. Some gemstones are particularly vulnerable to household chemicals and temperature changes. Cleaning gemstones presents special challenges.

Cleaning

After removing your gemstone jewellery, clean it with a non-abrasive jewellery cleaner. Do make sure, however that the jewellery cleaner specifies that it is safe to use with your particular gemstone. Use a soft cloth to remove any remaining dirt or other residue.

Storing

Store your gemstone jewellery in a lined case or a wrapped in a soft cloth, so the gems do not touch parts of other jewellery. Gemstones are harder than gold, silver or platinum and can damage the surfaces of your other fine jewellery if they are not kept separate.

Wear

While it's true that gemstones such as ruby and sapphire are second only to diamond on the hardness scale this is not a measurement of their durability. These gemstones are able to resist scratching almost as well as a diamond. Abrasive surfaces, harsh chemicals and sharp blows can damage even the hardest gemstone. Your gemstone jewellery should be the last thing you put on when getting dressed and the first thing you take off at the end of the night. Store your gemstones carefully and they will be enjoyed for generations.

This gemstone has been considered for centuries as one of the most precious coloured stones. Red is a universal symbol of power, love and passion. Until now, the determining characteristic of a ruby is its color: intense and deep. It’s no coincidence that the colour of the most expensive ruby in the world is named ‘dove’s blood’. Gemstones of such colour were found in Burma and they can be extremely expensive. Since the USA imposed an embargo on Burmese rubies in 2008 (later other countries endorsed the decision), the number of high quality rubies significantly decreased, and prices rose. However, this doesn’t mean gemstones from other countries (Thailand, Tanzania, Mozambique, Sri-Lanka, Kenya, Madagascar and Vietnam) and Burmese rubies (produced and certified before the embargo came into force - before 2008) cannot be used in jewellery.

Leaving politics aside and focusing on the color of this wonderful corundum – Rubies should be neither too dark, nor too bright, almost pink. The latter, in turn, causes disputes among gemologists, whether to consider this gemstone a ruby or classify it as another type of corundum – a pink sapphire. GIA experts define the color of a ruby with a sample kit.

The colour of a ruby and its attractiveness can vary depending on whether you look at it in lamplight or daylight. Thus, it is not recommended to buy jewellery with rubies without seeing it in daylight: some gemstones appear attractive in strong lamplight, and can be very unattractive in daylight.

Clarity is another important criteria for rubies. It should be noted that although the highest clarity degree for diamonds is “flawless”, there are no rubies without any inclusions. It is actually most important where the inclusions are located: the less noticeable they are the less they affect the beauty (and strength) of the gem, thus the better. Some inclusions can actually positively contribute to a gem’s aesthetics. For example, lathlike inclusions create a so-called asterism effect that is typical not only for rubies, but for some sapphires, spinels, beryls and garnets, i.e. a star shape figure appears on the gem’s cover due to lathlike inclusions – making it more unique.

An increase in a ruby’s weight affects its price dramatically, as high quality rubies of more than one carat are very rare.

Most often rubies come in cushion, oval, pear, round, emerald and marquise cuts.

Mohs scale: 9.0

Available colours: Red

Rough

Polished

Similar to ruby, a sapphire is valued for its colour. The most valuable one is blue, it is often called “a cornflower blue sapphire” – sapphires from Kashmir were valued for this very shade.

However, the sapphire’s colour palette is not limited by blue shades: they can be pink, purple, and yellow. They are all often used in jewelry. Although blue ones are the most valuable, the exception is the padparadscha sapphire; its unusual colour is described differently: it is called “sunset colored” and even “salmon colored”.

A sapphire can be a “chameleon” and change colour depending on light. This gem’s peculiarity is specified in a certificate, colour change is stated as “weak”, “moderate” or “strong”.

As well as rubies, blue sapphires often have some inclusions. Nevertheless, in comparison with rubies, the clarity of sapphires is higher. Sapphires with high clarity are very rare and are extremely valuable. Just like rubies, some inclusions can increase the price of a gem.

Referring to the aforementioned asterism effect. Along with rubies the more carats a sapphire has with other equal characteristics, the higher the price is. However, large sapphires can be found more commonly than rubies of the same size.

Mohs scale: 9.0

Available colours: Colorless, Blue, Green, Yellow, Orange, Brown, Pink, Purple, Gray, Black, Multicolored

Rough

Polished

An emerald is the third gem of the Big Three of gemstones. Similar to rubies and sapphires, it is valued for its color. Pure green or bluish – in some languages, an emerald is translated as “a green stone”, and it is no wonder that it has been considered for ages as the sample of green color in jewelry.

Often color variations can be explained by a gem origin, but in fact, gems of the same shade can be found in various deposits. If the color is more yellow or blue, then it is defined not as an emerald, but as another gem of the beryl group.

Color distribution in this gem is as important as the shade itself. The most valued gems are those with evenly distributed colour and have no so-called ‘color zones’.

Inclusions are common for emeralds. Moreover, many emeralds used in jewellery have inclusions that can be easily seen. An emerald with inclusions invisible to the naked eye is very rare now. The most important aspect is its overall appearance and impression.

When taking care and storing jewelry, with emeralds it is important to remember that an emerald is a softer gem according to the Mohs scale, especially in comparison to a diamond or corundum.

Thus, it is necessary to keep emeralds away from other gems and metals (especially during transportation).

Mohs scale: 7.5-8.0

Available colours: Green

Rough

Polished

This variety of beryl is valued in the jewellery world for its deep blue or green-blue color. The more pure and intense the color is, the more valuable the gem is (therefore, aquamarines are often artificially enhanced).

Large aquamarines of five or more carats can be found in jewellery. A remarkable distinction of this gem from others is that small aquamarines seldom have enough color intensity to look attractive. Thus, small gems of less than 5 carats can be sold at price per carat higher than bigger ones.

Mohs scale: 7.5-8.0

Available colours: Blue

Rough

Polished

Carnelian is a variety of chalcedony; it belongs to the quartz group. It can be either light-transparent or completely opaque. Its color varies from yellow and orange-red to pure red and red-brown.

Carnelian has been used since ancient times in the jewellery business, arts and crafts: even by Sumerian masters and masters in ancient Egypt and Persia. In ancient Rome, carnelian is also often found in jewellery – for example, it was the basis of cameos and intaglios.

Idar-Oberstein, German town, known by its lapidary art, was found in the XV century around carnelian and agate deposits.

Mohs scale: 7.0

Available colours: Red, Orange

Rough

Polished

Coral, especially its pink and red varieties, is widely used in jewellery and art. For example, coral amulets were found at excavations in Switzerland dated 8 000 BC. Coral was used in jewelry and decorative objects by the Sumerians, the ancient Egyptians and the Chinese.

A European Centre with a long tradition of creating jewellery and stone sculptures with coral is located in the city of Torre del Greco in the Italian region of Campania.

Actually, the Mediterranean Sea is the main source of pink and red corals. They can also be found commonly (commercial standard coral) in the waters off the coast of Japan and China.

Coral is especially valued for its shades, from pink to red – is becoming more and more rare (for instance, its production in the Mediterranean region from the 1970s to the 2000s was reduced by four times), that’s why there is a lot of refined coral on the market nowadays.

Mohs scale: 3.0 -4.0 

Available colours: White, Red, Orange, Pink, Gray, and Black

Rough

Polished

The most popular shade of garnet is red garnet. Jewellery with these gems was found in Egyptian pharaohs’ tombs. Moreover, garnets were known even in ancient Roman times.

In fact, the term “garnet” includes a large group of minerals of different colors and features. In addition to red garnets, spessartine (orange-red or pink-red variety of garnet), demantoid (green or yellow-green) and tsavorite (bright green) are also popular for modern jewellers. 

Mohs scale: 6.0 – 7.5

Available colours: Red, Green, Yellow, Orange, Brown, Pink, Purple, Gray, And Black

Rough

Polished

Jadeite, or jade is one of the most amazing and mysterious stones. The first peculiarity is the following: due to the fact that deposits containing best jadeite are located in the most hard-to-access and remote regions of upper Burma (and, incidentally, Burmese jadeite and rubies, as it was already mentioned, are prohibited by the embargo imposed by the United States in 2008 and supported by a number of other countries).

The second one is that real collectors and connoisseurs of jadeite are almost all from China. Therefore in China, high quality jadeite is appreciated more than high quality diamonds. At Sotheby’s and Christie’s auctions a bracelet rim made of jade can be sold for a million dollars.

Only in China they really distinguish the difference of color and transparency of jadeite and define a dramatic difference in price between jadeite of B class and A class, Imperial jadeite and jadeite of imperial color.

The most expensive – Imperial jade has emerald color, also named as 'Kelly Green' and has to be fully transparent, no parts of the stone should be opaque.

Due to the dramatic difference in price, varying by the color of jade, it is often ennobled.

Mohs scale: 6.0 - 7.0

Available colours: White, Blue, Red, Green, Yellow, Orange, Brown, Pink, Purple, Gray, Black, Multicolored

Rough

Polished

In recent years, lapis lazuli has become popular in high jewellery and this made the stone more popular.

The stone was known long ago, and it was often used in the form of beads, cabochons and engraved ornaments and shapes. It has been used in jewelry and in the works of stone sculptures.

When we say “lapis lazuli” most of us imagine the deep blue stone that resembles the night sky or the deep sea, but in fact the color of lapis lazuli varies and goes from green or purple, to turquoise and blue. Noble deep blue is the most appreciated shade of lapis.

The color can be pure or with golden pyrite inclusions – if they are nicely arranged on the stone’s surface, it will not lower its cost. But the presence of pyrite, making color greenish and faded can lead to a substantial price reduction. Moreover, the value of the stone decreases in the presence of whitish areas created by calcite.

The most valued lapis lazuli is often from Iran and Afghanistan (without calcite and with small amount of pyrite), the next most common source is from Russia with pyrite and small amount of calcite, and the least valued is Chilean lapis lazuli with the obvious presence of calcite.

Mohs scale: 5.0 – 5.5

Available colours: Blue

Rough

Polished

Malachite was widely used at different times and in various cultures. Ancient Egyptians, Greeks and Romans both used malachite for making ornaments and made malachite powder to use as green paint. In the Middle Ages malachite was believed to protect against the witches and "Evil Eye". In Russian culture malachite was poetized in Ural fairy tales adapted by the folklorist - author Pavel Bazhov (Ural was famous for its malachite deposits). 

Malachite with its beautiful shades of green and banded patterns is often used for manufacturing of vases, caskets and other objects for interior decoration, stone figurines and jewellery.

Currently major malachite deposits are in Africa. When purchasing malachite one should be careful and remember that synthetic imitations of this stone exist. 

Mohs scale: 3.5 - 4

Available colours: green

Rough

Polished

This variety of beryl was found relatively recently, just over 100 years ago circa 1910. It was named after the philanthropist Morgan who donated his large collection of morganites to the Smithsonian Institute. In Russia this gemstone was known under a different name by gemologists– vorobyevite, but now a universal name is used.

The color of this gem varies from light pink to almost lilac. It was very rare and expensive until a recent discovery of a mine in Mozambique, resulted in the reduction of morganite’s prices (although, prices are still relatively high).

Mohs scale: 7.5-8.0

Available colours: Pink

Rough

Polished

Opals were valued for their unusual colour and lights since ancient times. In some cultures they thought that lightning is confined within this gemstone. Nevertheless, in Europe opals were traditionally regarded as an unlucky stone - this was related to the poor technology of mounting the stone in jewellery: if the stone broke, it was considered as a forecast of failure. Opals returned to modern jewellery, devoid of any superstitious beliefs since 1980-s, when deposits of perfect opals were discovered in Australia. 

Depending on colour, lustre, and presence of admixtures - many varieties of opals are defined in gemology, however only few of them are used for jewellery. 

Fire opal, found mainly in Mexico is characterized by bright, fire-like splashes against the background of yellow to brown colour, occasionally changing to orange and red. Play of colour within the black opal takes place against the dark (not necessarily black) background colour. Same play of colour within the white opal takes place against the light background. Water opal is characterized by bright play of colour; it is usually transparent or semi-transparent. “Boulder opal” – variety of opal that is found as the interlayer within the rock. All these opals pertain to so called precious, or jeweler's opals, with characteristic opalescence – rainbow-like play of colours. 

Mohs scale: 5.5 - 6.5

Available colours: White, Colorless, Blue, Red, Green, Yellow, Orange, Brown, Pink, Purple, Gray, Black, Banded, Multicolored 

Rough

Polished

Paraiba Tourmaline is one of the newest gemological discoveries. Despite this, it is still considered a rarity. It was discovered in the late 1980s in the deposits located in Paraíba state, Brazil after which it was named. Neon-blue tourmaline stones are especially in demand nowadays.

Immediately after Paraiba tourmaline was found, it became incredibly valued, especially by Japanese collectors.

Quite quickly the deposits were exhausted and the stones – especially those that weigh more than a carat – have become incredibly rare.

Later on, mines of such tourmalines were discovered in Africa. To avoid confusion, it was decided to call the stones Paraiba-like or Paraiba-type. We should take into account that the price of the stone depends on whether it was found in Mozambique and Nigeria or in their “ancestral lands”- in the state of Paraiba; in the latter case the price increases dramatically.

Mohs scale: 7.0-7.5

Available colours: blue, green

Rough

Polished

One more gemstone that became popular due to the embargo on Burmese rubies is rubellite. In search of the right shade of red, many jewellers chose this type of red tourmaline. Thus, its red shade, resembling a ruby is most valuable – deep red, but other shades, such as candy pink, raspberry and purple, are also popular.

Mohs scale: 7.0-7.5

Available colours: Red, Pink

Rough

Polished

The embargo on Burmese rubies in 2008 played an important role in the history of the spinel. Although it was a difficult year for Burmese rubies, it was definitely a good one for spinel gems. The jewellery world turned to spinel as an alternative, and it became highly popular.

In fact, jewellers have been using this gem for centuries and the difference between ruby and spinel was almost indistinguishable; in fact around the middle of the XIX century gemological tests were not even accurate enough to distinguish red spinel from a ruby, and blue – from a sapphire.

A well-known historical precedent is the history of 170 carat “Black prince”, mounted in the front cross of the British Crown. For a long time “The Prince” was presumed to be a ruby and only when accurate tests appeared it was identified as spinel.

When the embargo on Burmese rubies was imposed, red spinel came to the jewellery foreground as a worthy substitute of red gems in jewellery. Later other spinel shades became popular; in the shades of blue, pink, orange, blue-gray, and black.

One of the most valuable spinel shades is deep red, a ‘strawberry colour’ – a gem of this shade can cost much more than many rubies.

An important peculiarity of spinel is that they look good both in daylight and in lamplight.

Mohs scale:7.5-8.0

Available colours: Red, Pink, Purple, Blue, Green, Orange,Yellow, Brown, Grey, Black

Rough

Polished

This blue-purple, lavender variety of tanzanite has recently become popular. It was introduced to the jewellery world in the 1960s. Tanzanite was discovered in Tanzania in 1967 and was named after the place of its discovery. Until now, Tanzania remains the main source of tanzanite production.

The stone was introduced to the market and registered by Henry B. Platt, the great-grandson of Louis Comfort Tiffany and a member of the board of directors of Tiffany & Co. He made it fashionable in the 1960s, immediately using it in jewellery made by this brand, having carried out a massive advertising campaign.

Mohs scale: 6.5-7.0

Available colours: Blue

Rough

Polished

This yellow-brownish ornamental stone is characterized by its special colour, silky lustre and polished surface.

The pattern of the stone is usually golden-yellow or golden-brown stripes or waves. Despite its name, this stone quite rarely has the effect of cat's eye - moving along the surface glare, which reminds of the cat's eye (reflecting the name). 

Tiger's Eye is used for the manufacturing of various objects for the interior decoration and jewellery. 

Mohs scale: 6.5 - 7.0

Available colours: Yellow, Brown, Multicoloured

Rough

Polished

Another stone that is quickly gaining popularity in fine jewellery is turquoise. It is known since ancient times and valued for its color: in the highest quality stones its colour resembles the sky on a clear sunny day. This shade is also called “Persian Blue” – and this name comes from the best source of this gem, Persia (present day Iran).

Turquoise has been highly admired in different countries and continents since ancient times. It was used in jewellery, decorative and applied arts, and interior mosaics. In ancient China, masters carved out figures and vases from turquoise, and the Navajos used pieces of turquoise as part of their bright ornaments.

Turquoise is not a very hard stone (5-6 points according to the Mohs scale), and it also has a porous structure. This affects its durability. Stones with a rough uneven surface may not be so durable, that’s why the most valued ones have smooth surface and a low degree of porosity.

In addition, the most valued is homogeneous colour surface, but there is one exception – when these inclusions form a beautiful pattern called a spider web, in this case it is considered unique and valuable.

Mohs scale: 5.0 – 6.0

Available colours: Blue, Green

Rough

Polished