Coloured Gemstones – Making the Right Choice!

Did you know? There are over 3,000 different minerals found on Earth! Of all those minerals though, only a small percentage qualify as gemstones.

Through the ages, people around the world have collected gems and used them for personal adornment, as emblems of power and representation of wealth. In many cultures gemstones have been associated with the month of birth, considering people are born under their “influence”. Nevertheless, the selection of coloured gemstones varies from country to country depending on availability, local traditions and fashion.

Beauty, rarity, hardness and durability are some of the factors that help us characterize gemstones. Each has a particular charm, colour and identity. Of course, popularity also affects price. It’s the universal law of supply and demand.

In order to choose a gem and further, to understand what makes one gem more valuable than another, consider these Five Essential Quality Characteristics:

1. Colour
The most fascinating feature of gems is that they come in almost every colour of the spectrum. Colour is evaluated by:

• hue (or shade of colour)
• saturation (or intensity)
• tone (or lightness/darkness)

2. Clarity
Flawless gemstones are both, very rare and valuable. Inclusions happen because of the way gemstones are formed in earth. They may be solids, liquids or gases. Some gems are more valuable because of their inclusions, which also provide clues to their identification, such as:

• horsetail inclusions in demantoid garnet
• insects in amber
• the three phase inclusions in Colombian emerald

3. Cut
Unlike diamonds, there isn't an "ideal" cut for maximum brilliance in gemstones, but rather, a high quality gemstone cut is one that presents:

• the most even colour
• the fewest inclusions
• and displays the majority of the gemstone weight when set in jewellery

In addition, gemstones can also be carved or shaped into a cabochon and beaded.

4. Size
Gems are sold by weight, not by size. The unit of measure is a carat, which is one fifth of a gram.

Gems that normally occur in smaller sizes, such as emerald, ruby, sapphire, alexandrite and spinel will be significantly more expensive when found as a larger stone because of its rarity.

And gems that naturally occur in larger sizes, such as amethyst, citrine, blue topaz and amber will not bear a remarkable price difference between larger and smaller stones

5. Enhancements
Almost all of the coloured gemstones available have been enhanced. Traditional methods like the heat treatment of corundum (for rubies and sapphires) and the colourless oiling of emeralds have been practised for several hundred years and are well accepted. However, recent treatments and new techniques like irradiation, bombardment, coloured oiling, filling by resins, high pressure/high temperature, etc. must be disclosed.

Other optical properties that gemstones may present are:

• Colour change with different light sources
• Pleochroism - two or three tones when viewed from different angles
• Lustre, the way light is reflected from the surface of a gemstone
• Interference, an optical effect giving a play of colour, as in opal, labradorite and ammolite.

An important characteristic of gemstones is their hardness. A diamond, because of its combined exceptional lustre and brilliant fire, is the hardest mineral on Earth and the most highly prized of all gems.

And last, choose the stones you like the best. That way you’ll be able to enjoy their natural beauty for a life time.