PRECIOUS GEMSTONES

There is an infinite variety of colour and texture in gemstones.

Scroll down (on mobile devices) or take your pick from the drop down list under the Precious Gemstones Tab above (desktops), for lots of information on some of your most popular precious stones: Sapphire, Ruby, Emerald, Aquamarine etc.

Many gemstones are too soft to use in rings which will be worn every day (see Mohs Scale, below). But there are still plenty to choose from, and if it is more of an occasion or dress ring, there are very few constraints.

You may also like to know more about Created Gemstones, which are an increasingly popular alternative to the mined variety.

MOHS SCALE OF GEMSTONE HARDNESS

Gemstones are classified by hardness up to 10 on Mohs scale. The hardest is Diamond at 10, and the softest mineral is Talc, at 1.

Ruby and Sapphire are forms of Corundum and are the next hardest, measuring 9 on the scale, while Emerald is rated at 7.5.

The most durable gemstones for jewellery have a hardness of 7 or more, examples include topaz, aquamarine, amethyst, citrine and other members of the quartz family.

Any gemstone with a hardness lower than 7 is easily scratched such as opal, moonstone, labradorite, pearl, amber, turquoise, lapis, kyanite, fluorite, apatite, onyx and prehnite.

It is worth noting that, even if a gem is rated at 7 or over, if it is also brittle, as in the case of Emerald, special care will still be needed when it is worn.

See Care of Gemstones for more information about how to protect all your gems and precious jewellery from damage.

CREATED GEMS, SIMULANTS & IMITATIONS

One thing we need to get clear from the start is the difference between Created (or Synthetic) Gemstones, Simulants and Imitations.

CREATED GEMSTONES

Created Gemstones, including Synthetic Diamonds, are chemically identical to the mined stones they replicate. They are very difficult to tell from naturally occurring gems and highly sophisticated equipment is needed to identify them. There are different, patented, methods for creating gemstones and they have their own recognised classification.

It is costly to produce Synthetic Gems and they take time to make, typically 3 weeks to 3 months depending on the method. So, although they offer a significantly less expensive alternative, they are not necessarily cheap.

Some people can be a bit sniffy about created stones, but they do have a place and advantages.

As is so often the case, their greatest strength is also their greatest weakness. Laboratory created gemstones are very pure and of very high quality. So Synthetic Rubies can look like the highest grade naturally occurring stones, and the same can be said of Synthetic Diamonds.

But this purity comes at the expense of the character which natural inclusions and variations bring to gemstones, particularly, for example, Emeralds.

However, the colours are very clear and bright, and Synthetic Sapphires are a particularly lovely shade of blue.

Apart from the significant cost advantage of synthetic gems there is also the security of knowing that these gemstones are just about the most ethically sourced you can find. No 'Blood Diamonds', no questionable mining or other working conditions, no ecologically damaging extraction or production methods and no risk that child labour is involved.

They are worth considering if you are one of the increasing number of people to whom these matters are top priority.

In the end, it is down to personal preference. To some people, it is the look which matters, and the lower cost is an added advantage. To others it is the mystery of the natural stone which captivates and for which they are prepared to pay the premium.

Whatever your preference, we can source the right gemstone for you.

SIMULANTS & IMITATIONS

Simulants can be natural stones which look like the gemstone they 'simulate' (ie appear similar to). Two good examples are White Sapphire and White Zircon, both of which are natural simulants of diamond.

White Sapphire is hard and rates at 9 on the Mohs Scale, although it does not have the brilliance of diamond, White Zircon is fiery, but softer at 6.5 to 7, and less practical as a stone in an engagement ring.

Imitation gems are simply made from coloured glass, plastics or resins. Included in this category are Swarovski crystals, which are either Cubic Zirconium (CZ) or leaded glass crystal. Imitations are easily identifiable as such by any competent jeweller.

SAPPHIRE

Sapphire is a variety of the mineral Corundum and is an aluminium oxide. Blue sapphires range in colour from pale blue to a deep indigo, the intensity of the colour depending on the amount of titanium and iron within the crystal. A medium coloured cornflower blue is the most desirable.

Sapphire also forms in a range of other colours, including colourless, pale pink, orange, green, yellow, violet and brown, called ‘fancy sapphires’. These different colour forms are due to some impurities within the mineral.

With a hardness of 9 on Mohs’ scale, Sapphire is a very durable gemstone for jewellery.

Find out more about Sapphires

RUBY

Ruby is the red variety of the mineral Corundum, of which sapphire is also a variety, and is one of the four precious stones. Only red corundum can be called ruby. (Pale rubies, are given the rather more enticing name of 'Pink sapphire'.)

Ruby is an aluminium oxide with traces of chromium, which creates the red colour. The range of reds varies with the individual deposits and locations. Traces of iron will create a more browny red. The most desirable colour is ‘pigeon’s blood’ - pure red with a hint of blue.

As a rough stone, ruby appears dull (as you can see from the rough mineral in the images), but when cut, the lustre can be almost as good as diamond. Inclusions in rubies are common.

Like Sapphire,Ruby scores 9 on Mohs’ scale, the most durable gemstone after diamond.

Find out more about Ruby

EMERALD

Emerald belongs to the beryl family of gemstones (beryllium aluminium silicate) and is one of the ‘precious’ gemstones. Aquamarine is from the same family.

The beautiful rich deep green colour of emerald is due to the presence of traces of chromium and vanadium.

The chemical elements present in emerald do not occur naturally in the same geographical areas. Due to its dramatic formation, emeralds often contain inclusions and minute fractures or fissures.

For thousands of years, emeralds have been treated with oils and resins to make the fissures less obvious, and to enhance the clarity of the stone.

Emerald is a hard gemstone, at 7.5 on Mohs’ scale, but it is brittle, so it should be protected in its setting and knocks must be avoided.

Find out more about Emerald


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