A Guide to Pearls and Stones

Coloured Gemstones

When selecting a coloured gemstone the same consideration should be given to cut, colour and clarity as in a diamond. A coloured gemstone should look bright, be lively and well cut.

At Natalie Barney we always look for an intense and consistent colour. A stone should be free from banding and patching unless it is characteristic of a particular stone e.g. Watermelon tourmalines & parti-coloured sapphires. Clarity is also important … it should be flawless or contain insignificant flaws. Strong flaws would not only be visually unsightly, they would also jeopardize the strength and stability of the stone.


There are four main factors which determine a diamond’s value; Cut, Colour, Clarity, and Carat Weight (often referred to as the four C’s). In addition there are two more C’s which we believe important to consider when purchasing a diamond: Confidence (in the product), and type of Certificate (gemmological report).


Cut is the most important and dramatic of the factors defining a diamond’s value and refers to the angles and proportions the diamond cutter has employed in fashioning the facets which turn a dull rough diamond into a sparkling, bright polished gem. Cut is the only factor defining a diamond’s value which dramatically affects the beauty, brightness and scintillation of a diamond. The better the cut, the more the diamond appears to sparkle and scintillate. Cut is also the only factor defining a diamond’s value over which man has any control.


Colour refers to the degree to which a diamond appears colourless. Diamonds are graded on a colour scale established by the Gemmological Institute of America (GIA) which ranges from D (colourless) to Z (light yellow). Diamonds which have tinges of yellow are more common than colourless diamonds and as such are less valuable than colourless diamonds. Completely colourless diamonds are graded “D” and are treasured for their rarity. As such they are extremely valuable.


Almost all diamonds contain minute pieces of non crystallised carbon. These identifying features are called inclusions. The size, nature, location, and amount of inclusions determine a diamond’s clarity and subsequently affect its value. A diamond’s unique inclusions were bestowed by nature when the diamond was formed millions of years ago deep beneath the earth’s surface. The fewer the amount of inclusions in a diamond the rarer and consequently the more valuable the diamond is.

Carat Weight

The weight of a diamond is expressed in a unit of measure called Carats. One carat is divided into 100 points. This means that half a carat is described as 50 points or 0.50 carats.Larger diamonds are found much less frequently in nature. Thus, for example, a one carat diamond will cost more than twice that of a 0.50 carat diamond (assuming colour, clarity and cut remain constant).


It is very important to ensure that when purchasing a diamond you receive the kind of everlasting value which can only arise from having the utmost of confidence in the product you have purchased.


Another important factor defining the value of a diamond is its certification through an internationally recognised and respected independent gemmological trade laboratory, for identification and grading.

South Sea Pearls

The South Sea Pearl is a labour of love. It takes two years for the host oyster to produce only one pearl. Each oyster is brought to the surface every second week to be very gently cleaned. A South Sea pearl can be round, near round, drop, button, baroque or circle … you cannot determine the shape whilst the pearl is in the oyster.

White South Sea Pearls

White South Sea Pearls are farmed off the West Coast of Australia near Broome. They come in White, Ivory, Pink, Silver, Grey and Blue.

Yellow South Sea Pearls

Yellow South Sea Pearls are farmed in Indonesian waters. They come in Cream, Yellow, Green, Champagne Rose and Gold.

Black South Sea Pearls

Black South Sea Pearls are also known as Tahitian Black Pearls, being farmed in Tahitian waters. They come in Aubergine, Green Peacock, Green, Peacock Green, Sea Green, Lime, Blue, Royal Blue Peacock, Grey, Grey Royal Blue, Grey Green, Grey Aubergine.