Coloured Gemstones

Overall Appearance

The objective in cutting, sculpting and polishing transparent gemstones is to enhance their exquisite brilliance, transparency and translucency. There are many classic outlines, the best known are ovals, rounds, cushions, emerald cut, pears, marquise, squares, triangles and cabochon style cuts. When evaluating the quality of cut, ensure that the gemstone has an even reflectivity and colour and that the shape is proportional.

Natural, Simulant and Synthetic Gemstones

Gem materials are occasionally treated to improve their appearance. The aim of treatments is to strengthen colour, improve clarity, improve lustre or improve durability. When buying a gemstone, you might also come across ‘simulants’. These can be artificial stones that imitate the appearance of a gemstone. Many important natural gemstones, including ruby, sapphire and emerald, have man-made counterparts that are manufactured in a laboratory. Such materials are called synthetics or created gemstones. In all cases, your jeweller should disclose whether they are selling a natural gemstone, a simulant or a synthetic as this information affects your purchase price, cleaning methods and repairs as well as replacement of an insured loss.


Pearls are one of the oldest gems on earth and need no cutting. They are organic gems created when an oyster covers an irritant/nucleus in the oyster with beautiful concentric layers of nacre. Cultured pearls are natural in the process of formation.

Akoya Pearls

They are the classic cultured pearls of Japan formed by the Akoya oyster ranging in size from about 2mm to 10.5mm. Their colours range from silvery white and cream to gold with overtones of rose and blue/green..

South Sea Pearls

Large pearls cultivated by the white-lipped oyster and are found in the warmer waters along the coasts of the South Seas. Colours are typically white, silver and gold with sizes from 9mm to as large as 20mm.

Tahitian Pearls

Large pearls cultivated by the black- lipped oyster and range from 9mm to over 16mm. Tahitian pearls range from natural dark colours to black with overtones of peacock and green.

Freshwater Pearls

Freshwater Pearls.

Guide to Birthstones

Representing strength, health and deep insight
Amethyst Purple Symbolises peace, love and happiness
Pale Blue
Symbolises courage and peace
Symbolises strength, courage and good fortune
Bright Green
Represents love, happiness in marriage and loyalty
Pearl Cream Symbolises faithfulness, purity, innocence and charity
Symbolises wisdom and a nurturing heart
Pale Green
Symbolises peace, love and happiness
Sapphire Deep Blue Signifies a creative spirit, new friendships and healthy relationships


Rainbow colors
Symbolizes faithfulness and confidence
Yellow to Brown
Signifies comfort, wealth and a creative spirit
Turquoise Sky Blue or Tanzanite Signifies valour, strength and wisdom


Tanzanite is a rare, precious gemstone that was discovered at the foothills of Mount Kilimanjaro, its only known source in the world. While some tanzanite is mined with natural bluish purple colours, most on the market have been heat-treated to enhance the colour. It is also estimated that the mining of Tanzanite will only continue for another 10-15 years. This adds to its special allure and popularity as an investment stone. Tanzanite is delicate and should be worn with great care. Its distinct cleavage plane means that tanzanite is a stone which has a lower durability and is more prone to chipping than most traditional gemstones. The quality, and therefore the value of cut tanzanite is judged based on a recognised set of criteria that has been established by the Tanzanite Foundation. This scale is similar to the criteria used to evaluate diamonds.

Pearl Grading


The thicker and more perfect the nacre/surface the higher the lustre.


The cleaner the surface the higher the quality.


Rounder pearls are more precious.


Pearls come in several natural shades. White-silver with slight rose overtone is the highest quality.


As with gemstones; the larger the pearl, the higher the value.