Precious Stones

How to select a Diamond – ‘The 4 C’s’


The 4 C’s represent the International standards applied to fine diamonds and other precious stones. Add to that Deirdre’s vast experience and you can be guaranteed the perfect diamond will be selected for your ring.

• An International Diamond certificate is always supplied.
• Deirdre supplies all shapes and sizes of precious stones.

Deirdre only uses stones from reliable and trusted sources who are signed up to the Kimberley Process Certificate Scheme.

Cuts of Diamonds


For further information on diamonds:


The hardest known naturally occuring material, rated as 10 on the Mohs scale of mineral hardness. Diamonds are formed about 100 miles down in the earth’s mantle at very high temperatures and pressure. They come to the earth surface only when volcanic eruptions occur.

CUT – Perspective and magnitude of a diamond.
Diamonds have many variations of cut with the most popular being: Brilliant, Princess, Emerald, Asscher, Radiant, Oval, Pear, Marquise, Heart, Trillian, Square and Baguette.

COLOUR- Level to which a diamond is colourless.
• Colourless diamonds are the most sought after as they return the most light.
• Colour is determined on a scale from D (clear) to Z (light yellow or brownish tinting).

CLARITY – Occurrence of inclusion in a diamond.
• A diamond’s clarity is judged on a scale from FL (flawless) through IFL (internally flawless), VVS1 (very, very small inclusion), …all the way to I3.
• The clearest stones have the fewest inclusions and so absorb the least light – making them more radiant, thus more sought after.

CARAT – Weight of a diamond.
• Diamonds are sold based on the weight in units not based on the size of it.
• The standard unit of weight is carats.
• Diamonds were originally measured against carob tree seeds!


A variety of the mineral Beryl, todays emeralds were formed hundreds of millions of years ago and are found in dark shales and limestones deposits in Columbia, Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia. Top quality, fine emeralds are rare so this means that the price of a top quality emerald may be higher than that of a diamond of the same weight.

In the case of emeralds, colour and clarity dominate the desirability and price of an emerald.

• It is generally believed that the more intense and most radiant green of an emerald, reflects the value and desirability.

All emeralds have inclusions. These inclusions are characteristics unique to the formation of emeralds and help identify between natural and created (or synthetic) Emeralds. So unlike in diamonds,
inclusions do not detract appreciably from the value of the emerald.

These have a secondary effect on emerald values. Very large emeralds are quite readily available but you will need to settle for lighter tones, less intense colour and reduced brilliance. However, very fine grades of emerald over one carat are rare, hence may rival or exceed the value of diamonds of equal carat weight and grading.


Belong to the class of minerals called Corundums (like Rubies), rated as 9 on the Mohs scale of mineral hardness, which makes it second only to diamonds. sapphires are found in India, Burma, Sri Lanka, Thailand, Vietnam, Australia, Brazil and Africa.

An intense, rich, full blue is the colour most associated with sapphires, but in actual fact they come in a huge variety of colours. These colours are known as fancies and range from the highly prized Padparadscha (a beautiful pinkish-orange) to pink; orange (medium-dark red-orange); purple; yellow (vivid light-yellow) and green.

• Sapphires are denser than diamonds, so a one carat sapphire could be considerably smaller than a one carat diamond.

• The degree of visibility through a sapphire is known as its transparency.
• The lighter and more transparent sapphires usually have excellent brilliance despite any inclusions they may have.

The most popular cuts are: Step/Emerald, Brilliant, Mixed and the antique Cabochon Cut.


Sapphire Gem


Described as “the king of the gemstones”. They are the red variety of Corundum and as with sapphires the combination of hardness and rich colour makes these gemstones highly valuable.

Colour is a ruby’s most important feature.

• An exceptionally vivid, rich, full red with a slightly bluish hue, sometimes referred to as ‘pigeon-blood-red’, is highly prized for its unique brilliance in any light, be it natural or artificial.
• The best come from the Mogok region of Burma.

• As with sapphires, rubies are denser than diamonds, so a one carat stone will be smaller than a one carat diamond.
• Rubies of more than 3 carats are very rare, so can achieve top prices, surpassing the price for diamonds


Pearls are gems, created when a living oyster covers a foreign object with layers of nacre. The finest quality natural pearls have been highly valued as gemstones for many centuries, as thousands of oysters had to be searched for just one pearl.

• The most valuable pearls occur spontaneously in the wild, but are extremely rare
• Today pearls are cultured or farmed
• Most cultured pearls are produced in Japan
• In the South Pacific, oysters produce South Sea cultured pearls and Tahitian black cultured pearls, which are larger in size
• Freshwater pearls are cultured in mussels, mostly in China

The quality of pearls is judged by the soft iridescence, lustre and shine of the surface. Fine pearls  have no flaws or spots and have an even, smooth texture. Other factors which affect value are the regularity of the shape, size, and colour: rose tints are the most favoured. To distinguish between an imitation pearl and a cultured or natural pearl, simply rub a pearl gently against the edge of your tooth. The cultured and natural pearls will feel slightly rough, like fine sandpaper. Imitations will feel smooth because the surface is moulded or painted on a bead.

Caring for your Pearls
• Pearls are a soft gem, clean them with a dry or damp soft cloth
• Never use detergent or bleach on them
• Nor should you ever try to remove dirt with a toothbrush or any abrasive material as these may scratch the pearl’s surface
• Clean pearls regularly rather than allow a build up of dirt or make-up
• Put on pearls after applying make-up, perfume, deodorant or hairspray.
• Take off pearls before showering, bathing or swimming so you don’t get the silk thread wet
• Restring your pearls about once a year
• Keep your pearls in a soft bag to stop them getting scratched