Buyer's Guide The True Value of a Diamond The Value of the Black Pearl The Value of Gold Choosing a Gem The True Value of a Diamond The 4Cs The true value of a diamond is based on its rarity. Every diamond has its own unique set of characteristics – the 4Cs. Colour, clarity, carat and cut are the combined qualities that define a diamond’s true value. Colour 23 shades of white Diamonds are found in a range of colours from brown to very rare pinks, blues, greens and other fancies. However, the best colour for a diamond is no colour. The shade of a diamond is graded from D to Z. Exceptionally white or colourless diamonds are extremely rare. Those graded at the lower end of the alphabet are the most common light yellow diamonds. Clarity The passage of light Almost all diamonds contain non-crystallised carbon or other minerals. These are known as inclusions. The fewer and smaller the inclusions, the greater the clarity of the diamond as more light will passage through it. The clarity of a diamond is graded according to its inclusions. A diamond with zero inclusions is known as Flawless, FI, LC or IF, and as diamonds decrease in clarity they are graded from VVS1, VVS2, VS1, VS2, SI1, SI2, P1, P2, to P3 at the lowest end of the scale. Cut Adding the sparkle The cut, rather than the shape, of a diamond determines its brilliance and value. When a diamond is cut well by a master diamond cutter, it acts like a mirror refracting light all around, increasing its brilliance, fire and exquisite beauty. The six most popular shapes of diamonds are: Add in the diagram of the diamond shapes and label accordingly as follows: Round Brilliant , Oval, Marquise, Pear, Heart, Emerald, Princess, Radiant Carat Size doesn’t always matter A diamond’s weight is measured in carats. One carat is equal to 0.2 grams and one hundred points. However, the more points a diamond has does not necessarily reflect a greater value. This is dependent upon its colour, clarity and cut. Back to Top. The Value of the Black Pearl Black pearls vary greatly in their six characteristics, and it is said that no two pearls are exactly the same. The Six Qualities of a Black Pearl Coating A pearl is formed by layered coatings of nacreous secretions over a nucleus. It takes thousands of crystalline layers to form a pearl. The thickness, fineness and smoothness of these layers determine the quality of a pearl’s coating. Lustre Lustre consists of two types of light – that reflected by the pearl’s surface, and that reflected by crystal layers within the pearl. These two types of light interfere, causing the depth of lustre and the pearl’s shimmer. The finer and thinner the layers on a pearl, the greater the lustre. Colour The colour of a pearl is determined by the colour of its layers, which can be red, yellow and green, and the colour caused by light interference. The colour of a black pearl is classified as black, green, red, grey, blue, white and peacock green. Size Cultivated for an average of two years, pearls generally grow by 0.7mm to 1mm a year. Harvested pearls average 9-14mm in size, though advances in cultivation technology have produced even larger pearls. Shape and flaws Black pearls are classified in the following six shapes: round, drop, oval, circle, baroque and Keshi. Black pearls characteristically have warps and flaws which occur during nacre (layer) formation. Therefore, the smoother the black pearl, the rarer and more valuable it is. Smooth, drop-shaped pearls have become highly valued in Europe and the US. Matching Necklaces of black pearls contain pearls matched in colour, shape and size. Because each black pearl is highly individual, it is extremely difficult to find pearls of the same quality needed to form a necklace. Hence, a necklace of black pearls is valued comparatively higher than those of other types of pearl. Back to Top. The Value of Gold Gold, though characteristically yellow colour, can also be black or ruby when finely divided. These colours are the result of gold's plasmon frequency lying in the visible range, which causes red and yellow light to be reflected, and blue light to be absorbed. Only silver colloids exhibit the same interactions with light, creating the yellow often seen. Gold is the most malleable metal in existence. A single gram can be beaten into a sheet of one square metre. Gold readily forms alloys with many other metals. These alloys can be produced to increase the hardness or to create exotic colours. Adding copper yields a redder metal, iron - blue, aluminium - purple, platinum metals - white, and natural bismuth together with silver alloys produce black. Native gold contains usually eight to ten per cent silver. Like other precious metals, gold is measured by troy weight and by gram. When it is alloyed with other metals the term carat is used to indicate the amount of gold present, with 24 carats being pure gold and lower ratings proportionally less. The price of gold is determined on the open market, but a procedure known as the Gold Fixing in London provides a twice-daily benchmark figure to the industry. White Gold White gold is an alloy of gold and some white metals such as silver and palladium. White gold can be 18kt, 14kt, 9kt or any carat. For example, 18kt yellow gold is made by mixing 75% gold (750 parts per thousand) with 25% (250 parts per thousand) other metals such as copper and zinc. 18kt white gold is made by mixing 75% gold with 25% other metals such as silver and palladium. So the amount of gold is the same but the alloy is different. Rhodium plating is used to make the white gold look whiter. The natural colour of white gold is actually a light grey colour. The Rhodium is very white and very hard, but it does wear away eventually. To keep a white gold ring looking its best, it should be re-rhodium plated approximately each 12 to 18 months. Platinum Platinum is a white metal, but unlike gold it is used in jewellery in almost its pure form (approximately 95% pure). Platinum is extremely long wearing and is very white, so it does not need to be Rhodium plated like white gold. Platinum is, however, very expensive. A platinum ring will be approximately twice the price of an 18kt white gold ring (excluding gemstone costs). Back to Top. Choosing a Gem A gemstone is the naturally occurring crystalline form of a mineral, which is desirable for its beauty and valuable in its rarity. There are more than 30 popular gem varieties and we have highlighted some of the more popular ones here. GEMSTONE VARIETIES   Emerald The lively luminosity of its colour makes the emerald a unique gemstone. However, really good quality is fairly rare, with inclusions often marring the evenness of the colour. Fine inclusions, however, do not decrease its value. On the contrary, even with inclusions, an emerald in a deep, lively green still has a much higher value than an almost flawless emerald whose colour is paler. Pure sophistication Whilst its hardness protects the emerald to a large extent from scratches, its brittleness and its many fissures can make cutting, setting and cleaning rather difficult. Even for a skilled gem cutter, cutting emeralds presents a special challenge, firstly because of the high value of the raw crystals, and secondly because of the frequent inclusions. Emeralds are cut in many different ways, but a special cut has been developed just for this gem: the emerald cut. The clear design of this rectangular or square cut with its bevelled corners brings out the beauty of this valuable gemstone to the full, at the same time protecting it from mechanical strain. Today, many emeralds are enhanced with colourless oils or resins. This is a general trade practice, but it does have the consequence that these green treasures react very sensitively to inappropriate treatment.  Ruby The ruby is the red variety of the corundum mineral, which also includes the sapphire. Pure corundum is colourless. Slight traces of the colour creating elements such as chrome, iron, titanium or vanadium are responsible for the colour. One of the hardest minerals on Earth, they are second only to diamonds in their hardness. Only red corundum may be called Ruby, any other colour is called Sapphire. Colour is everything Colour is the ruby’s most important feature, and transparency is secondary. Therefore, inclusions do not affect the quality of a ruby, unless they decrease the transparency of the stone or are located right in the centre of its table. The cut is essential: only a perfect cut will underline the beauty of this valuable and precious stone appropriately.  Sapphire The sapphire belongs to the corundum group, as does the ruby. They are second in hardness to diamonds only, and diamonds represent the hardest mineral on Earth! Because of their hardness, sapphires are easy to care for as gemstones and demand from their wearers only the usual and normal care. Blue is the sapphire’s main colour, but there are other colours. Sapphire blue has become a colour related to anything permanent and reliable, and this is one of the reasons why women in many countries settle on the sapphire for their engagement rings.  Amethyst  Opal Opals shine and sparkle in a continually changing play of colours, which experts describe as “opalising”. Depending on the kind, place of occurrence, and colour of the main body, opals are differentiated as: Dark or Black Opal, White or Light Opal, Milk or Crystal Opal, Boulder Opal, Opal Matrix, Yowah Nuts from Queensland – the so-called “picture stones“, and also Mexican and Fire Opal. If Opals are lacking the typical play of colours, they are simply named “Common Opal”. In order to best bring out the play of colour in a Fine Opal, the stones are cut and polished to round or oval cabochons, or any other softly domed shape, depending on the raw material. Only the best qualities of Fire Opal, however, are suited to faceting. Opal loves to be worn on the skin Opals can become brittle due to their water content – usually between two and six per cent, but sometimes even more. If stored too dry or exposed to heat over a longer period of time, Opals will show fissures and the play of colour will become paler. Therefore, Opal jewellery should be worn as often as possible, for then the gemstone will receive the needed humidity from the air and from the skin of its wearer.  Topaz  Tourmaline  Peridot  Rubellite Tourmaline  Aquamarine  Green Tourmaline  Citrine  Paraiba Tourmaline  Ametrine  Yellow Tourmaline  Garnets  Blue Tourmaline  Tsavorite Garnet  Multicored Tourmaline  Demantoid Garnet  Tanzanite  Mandarin Garnet  Lapis Lazuli  Fancy Sapphires  Quartz  Jade This gem is mainly green but it is also found in shades of white, grey, black, yellow, and orange, and in delicate violet tones. Known to Man for some 7000 years, in prehistoric times it was considered an ideal material for weapons and tools. Yet as early as 3000 B.C. jade was known in China as yu, the 'royal gem'. In the long history of the art and culture of the enormous Chinese empire, jade has always had a very special significance, roughly comparable with that of gold and diamonds in the West. What is jade? 'Jade' is a generic term for two different gems, nephrite and jadeite. It was not until the beginning of the 19th century that mineralogists and gemmologists started to differentiate between them, since they bear a considerable resemblance to each other in terms of their appearance, their hardness and the properties they exhibit when being processed. Both are tough, since they consist of dense, close-grained, matted aggregates, but they differ from one another in their chemical composition and colours. Only in the very finest jade is the colour evenly distributed. Both nephrite and jadeite often have veins, blemishes and streaks running through them, though these may not always be regarded as flaws. On the contrary, some of these patterns are considered particularly valuable. What distinguishes good jade? In general, the value of jade is determined according to its colour and the intensity of that colour, the vivacity and texture, and its clarity and transparency. Likings for particular colours vary very considerably from region to region and culture to culture. In the USA and Europe, emerald green, spinach green and apple green are regarded as particularly valuable. In the Far East, on the other hand, pure white or a fine yellow with a delicate pink undertone is highly esteemed. In the world of jewellery, the fine violet nuances of lavender jade are very popular. It is however the rare, emerald green of imperial jade, which fetches the highest prices. Unfortunately, since not only good and natural jade is offered for sale, but often fake or poor-quality products or stones which have been coloured or otherwise treated, it is advisable to buy good jade only from reputable dealers and jewellers. In recent years, creative jewellery and gemstone producers have come up with some wonderful modern jewellery designs to update the image of jade.  Zircon  Iolite  Spinel  Fire Opal  Moonstone  Alexandrite  Chrysoberyl  Kunzite  Beryls  Morganite  Chrome Diopside  Andalusite  Amber  Turquoise  Coral  Agate  Onyx  Bloodstone  Jasper  Pearl  Diamond   Back to Top.

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