Cheat Sheet

Buying Gemstones For Dummies (Australian Edition)

While people often admire or even drool over gemstones and the jewellery they’re made into, most people don’t know much, if anything, about shopping for gemstones and their settings. You need some basic knowledge about buying gemstones and gemstone jewellery, as well as the skills to recognise a high quality natural gemstone.

How to Buy a Diamond

Mostly people buying gemstones are interested in looking at diamonds: They’re still the favourite. When you’re buying diamonds or shopping for diamond jewellery, you should always take a jewellery or hand loupe with you or borrow one from your jeweller. Clean the diamond thoroughly before you look at it with a soft cloth.

These are the things you need to ask your jeweller when buying a diamond:

  • Is it a natural diamond and not a synthetic or imitation? Natural diamonds have formed at great depths in the Earth’s crust, at extremely high temperatures and pressures, and have taken many millions of years to do so.

    Certain substances have been substituted for diamond, such as cubic zirconia (CZ) and synthetic moissanite; as well as zircon; glass; synthetic rutile, sapphire and spinel; and man-made garnets like GGG and YAG.

  • Can you guarantee that it’s not a conflict diamond? Conflict diamonds, also known as ‘blood diamonds’, are natural diamonds which have been illicitly mined and sold to finance wars and civil unrest, mainly in certain African nations. Ask your jeweller if he or she can provide you with a Kimberly certificate, which states that a diamond’s sale has not financed war. Diamonds mined in Australia or Canada are not blood diamonds.

  • What is the diamond’s exact grading: carat weight, colour, clarity and cut? Diamond quality is graded by reference to the 4Cs — carat weight, colour, clarity and cut. Diamonds are weighed in carats (1 carat = 1/5 of a gram), or in points (100 points = 1 carat) for smaller diamonds. Most people think of diamonds as ‘white’ or clear, but diamonds come in many colours.

    Generally, the ‘whiter’ the diamond the better, unless you are fortunate enough to have an intense fancy coloured diamond. Clarity refers to freedom from internal inclusions and external flaws, and the cleaner a diamond is the better. A diamond usually sparkles best with a brilliant cut, which was designed especially for diamonds.

  • Has your diamond been clarity enhanced? Some diamonds are clarity enhanced usually by fracture filling and laser drilling. Fracture filling involves filling cracks or breaks with a colourless substance to hide them. Laser drilling is used to make inclusions less visible and so improve a diamond’s look. Ask your jeweller whether a diamond has been clarity enhanced and, if so, how.

  • What is the shape? The term ‘cut’ does not refer to shape. Shape refers to the outline of a diamond’s edges. A diamond may be round, square, rectangular, marquise, pear, trillion or heart shaped. Whatever its shape, the quality of the cutting must be judged, too.

  • Does it have a good ‘make’ (proportions)? The term ‘cut’ is also referred to as a gemstone’s ‘make’. When you judge cut, you’re really considering a gemstone’s proportions and finish. It is these two factors that determine a diamond’s fire (flash) and brilliance (life), no matter what cutting style or shape. In a well-proportioned diamond, the height of the crown should be a third of the pavilion depth.

  • What are the exact millimetre dimensions of the stone? When buying gemstones you should be told its exact dimensions in millimetres (size), in addition to its carat weight.

  • Is the diamond accompanied by an independent grading report? An independent grading report is an objective assessment that identifies and describes an unmounted diamond. However, it is neither a legal certificate nor an appraisal, which gives a subjective value or price attached.

    Most independent grading reports include the date; type of gemstone; shape and cutting style; weight; dimensions; proportions (depth, table, crown, pavilion, girdle, culet); colour grade; clarity grade; cutting and finish (polish and symmetry) quality; fluorescence; and diagrams showing inclusions (types and locations).

How to Buy a Quality Coloured Gemstone

Colour is the most important consideration when buying coloured gemstones; the colour component of a coloured gemstone is between 50 to 70 per cent of its value.

Here’s what to look for when you’re shopping for coloured gemstones:

  • Determine whether the gemstone is a natural, an imitation or a synthetic. Natural gemstones are produced by nature with no human interference. Synthetic gemstones are man-made in a laboratory, and they share the natural stone’s chemical, physical and optical properties.

    Imitation stones are simulants that do not share the natural gemstone’s properties. Shopping for imitation and synthetic stones can be fun, but you don’t want to be paying a natural gemstone’s price for them.

  • Clarify the name of the gemstone. Be aware of misleading names such as Australian jade (which is really chrysoprase quartz), Balsa ruby (a red spinel), Evening emerald (peridot) and Brazilian sapphire (blue tourmaline).

  • Check out how the colour looks in a variety of lights. Remember that daylight varies throughout the day and where you are in the world. A high quality coloured gemstone should look good under all lights; it should be a bright, intense, pure, rich and vivid colour.

  • *Be aware that coloured gemstones are rarely as ‘clean’ as diamonds, and should be judged differently. There is no universally accepted standard for grading the clarity of coloured gemstones, although the Gemological Institute of America (GIA) has developed its own standards.

  • Ask whether the coloured gemstone is enhanced. Gemstones that have been enhanced need different care and cleaning treatments so you need to know if you’re buying an enhanced stone. Ask your jeweller; for example, has this blue sapphire had diffusion treatment, or has this emerald been oiled?

  • Determine the quality of the cut, which is what gives any gemstone its beauty and brilliance. An ideal cut reflects the light in an even manner, without any dark areas or windowing (where a too-shallow or poorly proportioned stone lets the light straight through reducing the brilliance of the gemstone).

  • Shop around and compare lots of stones before you buy. Unlike diamonds, the market for coloured gemstones is highly fragmented with no central marketing organisation. Grading and pricing is much more subjective. So you really must shop around.

  • Do you really like the gemstone? Does it complement your skin tones? Would you like to be partners for life and pass it on to future generations?

How to Pick Out a Precious Opal for Purchase

If you’re shopping for opals, know what type you’re buying and choose the one that you like the best in your price range. Be aware that solid opals are best, whether they be black opals, white opals, boulder opals or crystal opals.

Composite or assembled opals as doublets and triplets can look spectacular, but they are not nearly as durable. If you’re buying opals from the Internet remember that a photograph simply can’t accurately portray a natural opal.

Here’s what you need to know when buying an opal:

  • What type of opal it is. Australia produces over 95 per cent of the world’s opals. Each of the different types comes from a different part of Australia and each looks very different to the others.

    Black opals from Lightning Ridge are the ‘Rolls Royce’ of opals and are rare and expensive. Boulder opals come from Queensland opal fields and can have stunning colour, but they also have a natural ironstone backing which adds to their weight (so beware of being sold boulder opal as a price per carat), but which also makes them stronger.

    Crystal opals have a translucent or transparent quality, and those with a good colour as well can fetch high prices. White opals come from South Australian opal mines, and have a ‘milky’ white body tone, which often results in the colour being less bright; however, a good quality white opal is still a wonder to behold.

  • Compare, compare, compare. Look at as many different types of opal as you can, and when you’ve decided on which type you like best, establish whether the one you keep coming back to is solid or a composite stone (a doublet or triplet). Solid opals are most durable, but they’re also more expensive.

  • Determine the quality of the opal. To judge an opal, consider its play of colour, body tone, brilliance, pattern, the thickness of the colour bar, and any faults such as cracks or inclusions (natural inclusions are acceptable but never buy an opal that’s cracked).

  • Choose an opal that you love and one that goes with your skin tones. While red on black is the most desirable and the most valuable (followed by orange, yellow, green and most common is blue), if you prefer blues and greens then go for it.

  • Consider the brilliance of the opal. The brilliance or brightness is one way the value of an opal is judged. There are three ratings: Brilliant, Bright and Subdued; with ‘brilliant’ being the brightest and most expensive, ‘bright’ in the middle range, and ‘subdued’ having the least brightness. Brilliant opals are fabulous but even subdued opals can be lovely.

  • Always get a certificate of authenticity. Obtaining a certificate when you buy an opal is good for insurance purposes and re-sale value, and it makes the seller accountable.

  • Take advantage of paying no GST. If you’re a tourist in Australia, or you’re an Australian who’s travelling overseas and doesn’t mind taking it with you, you don’t have to pay the 10 per cent Goods and Services Tax when you buy opals, or you may receive a refund of the amount if you do.

  • Remember that opals are quite fragile and require extra care. Opals don’t respond well to sudden temperature changes so setting an opal in a piece of jewellery requires the skill of an expert. If you’ve chosen a loose opal that you want set in jewellery ensure it’s set by someone who really knows opals.

What to Look For when Buying a Pearl

Natural pearls are quite rare because they’re a random product of nature that occurs less and less frequently due to pollution and over-fishing. You can readily buy cultured pearls, however; which are natural pearls created with human assistance.

Both natural and cultured pearls form from an irritant that molluscs protects themselves from by secreting successive layers of nacre, which is an organic substance composed of aragonite and conchiolin. Imitation, faux or stimulated pearls do not possess nacre; they are usually glass, plastic or shell beads dipped in ground up fish scales and coated with a lacquer.

When buying a pearl or pearls this is what you need to remember:

  • Natural pearls are extremely rare and outrageously expensive, so you’ll probably be looking at types of cultured pearls. Familiarise yourself with the different types: saltwater South Sea, Black Tahitian and akoya pearls; and freshwater pearls.

  • When judging pearls firstly consider nacre. Natural saltwater and cultured freshwater pearls are solid nacre, while cultured saltwater pearls have a nucleus that’s surrounded by layers of nacre. The number and thickness of the layers of nacre is what’s important in determining the quality of a pearl. And, in turn, this produces the inner glow of a pearl; the soft, satiny sheen — its lustre — which will influence its value.

  • Check out the colour. Pearls come in a wide range of colours and you should consider a pearl’s main body colour, its overtones (say, a white pearl with gold or rose overtones) and its orient (iridescence), which means the play of light interference across the pearl’s surface or just beneath it. Natural colours are best, but you can also buy pearls dyed various colours.

  • Pearls are graded according to the smoothness of their surface. Blemish-free pearls demand a premium; small spots on a pearl don’t decrease the value as much as chips or cracks.

  • Round or spherical shapes are most desirable. But pearls can look beautiful in all sorts of shapes. If you’re having a necklace or bracelet made ensure you have matching shapes and sizes.

  • Generally, the larger the diameter of a pearl the more expensive it will be. The price of a pearl increases exponentially as its size increases.

  • Pearls can be graded on one of two scales. No standardised, industry-wide pearl grading system has been established, but your jeweller may use one of two commonly used grading systems: the AAA-A and the A–D systems. If your jeweller refers to a grading, for example AA, ask exactly what he or she means by that. Ask if you can read a description of each grading term so that you know what each term used means.

  • Pearls are soft (3 on Mohs’ scale, which measures a gemstone’s resistance to scratching) and they’re porous, so be prepared to look after them. Necklaces and earrings are a safer option than rings or bracelets, which are more easily damaged when you wear them.

  • Always get a detailed certificate of authenticity with your purchase. A certificate states the quality of your pearl and contains a detailed description of your jewellery, which is handy in case you ever need to make an insurance claim.

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