Ranking a 7 to a 7.5 on the moh scale of hardness they are excellent wearing with and there wide variety of colours has made them a very popular gemstone for jewelery with many designers using them due to the inherent versatility of the gem. They are mined in many places across the world and what is interesting is that according to locality the colour of the Tourmaline will often often change. Yellow or ‘canary’ Tourmalines are prevalent in Malawi while in Paraiba in Brazil they are famed for their intense blue and blue-green stones.

The massive amount of variation within the trade leads to problems when trying to tie price to an invariant figure. As with all gemstones Tourmaline is priced due to rarity and while as a stone it is not hugely rare the individual variations can increase the price substanstially.

However, they are not just interesting in terms of apperance, in terms of physical science they are interesting gems also. They exhibit pyroelectricity which means that when heated and allowed to cool they will temperily emit electricity and create a voltage. Scientists are not completely sure how Tourmalines do this, because although they know the crystal structure is changed in heated the exact mechanics are not currently known.

The shimmer of colour as light moves through it is due to the different layers of feldspar that make up it’s internal structure. These layers have different refractive indexs and therefore they slow light at different levels which creates refractioned light through one which is then refracted again through the other layers.

It is commonly mined in Australia and Sri Lanka but there have been numerous deposits of moonstone found the world over. Furthermore, it is not a new gemstone, there are records that show it was around during the age of the Romans, where they believed it was created by frozen moonlight. Although not a particuarly rare stone it is nonetheless a beautiful one and when cut into cabochon shapes they become very popular jewelery pieces.

With a rating of 6.5 on the moh scale they are hard enough to withstand some wear but they can easily be chipped or scratched so care must be taken when wearing one to not expose it to too many extrememe conditions.

The reason for opal’s incredible refraction ability is due to it’s structure. Silica spheres arranged in planes, or rows, that taper to a pyramid shape, the spacing and posistioning of the planes, in response to the angle of refraction determined by the appropriate angle of incidence, that causes the dispersion of light leading to incredible refraction. To give you an idea of how well light is refracted in opal, opal’s refractive index is 1.45 which means that in a vacuum light travels 1.45 times faster than it does in opal, (as a point of reference, water’s refractive index is 1.33).

Clarity is difficuilt to measure in opal due to the extreme commonality of ‘veins’ within opal which instead of being seen as a disadvantage are essential to the distinctive light performance that makes opal’s so sought after. Instead opal’s are ranked either translucent, semi-translucent or opaque. Opal’s are often treated, commonly with oils, and this is one of the main reasons that they cannot be placed in an ultrasonic cleaner. The other is the porous quality of opal (some opal’s can be 30% water), means that the cavatation process used in ultrasonic cleaning would shatter the opal.

In terms of cut, a cabachon cut is usually used, to avoid abrasion and enable the best range of light play through the opal. Although this can still be used in it is different to the usual apperance. But that could be perfect.

Amber is most commonly associated with the orange colour to which it gives it’s name, but amber is also common in yellow, brown and ocassionally green and blue. The blue amber is, as of the time of writing, only found in one place in the world, the Dominican Republic, and called Dominican Blue Amber. Dominican Blue Amber is actually a transparent white colour but when sunlight enters the amber it is refracted within the amber which then emits a blue hue. However, when the amber is viewed under artificial light it looks white.

Baltic amber, which is probably the amber you have seen most of, is almost always the orange colour, and does not change colour like the Dominican Blue Amber. Because amber is so soft, a 2.5 on the moh scale of hardness it is rarely step cut as other gemstones are, but it can still be used in engagement rings. Furthermore most amber has airbubbles inside the amber, these airbubbles affect the light performance of the amber and lead to a cloudy or milky appearance. Milky amber is filled with so many of these airbubbles that when viewed through a microscope resembles sea foam.

Amber is also an incredible preservative, with fully preserved fossils of insects that are at least 60 million years old. Furthermore, scientists have recently extracted the oldest specimen of DNA from amber that was 40 million years old.

Because of the large amount of inclusions common in emeralds they are not graded for clarity under magnification, instead a trained eye checks if there are any inclusions. In this way an emerald can be considered flawless if there are no inclusions visible without magnification, even though it is almost certain that the emerald will have many inclusions. Because of this clarity is not normally given too much weight when deciding to buy an emerald or not, although it is certainly important, colour is generally deemed more important.

Emeralds are also frequently treated to enhance appearance with heat-treating to enhance colour, while an oil finish appears to improve clarity and is not frowned upon within the emerald industry as it is for other gemstones. Furthermore, some emeralds are filled with lead glass to further decrease the impact and appearance of inclusions, but this practice is normally frowned upon. Emeralds have found many uses in the jewelry world, whether it be as or engagement rings, they are beautiful alternative that is sure to draw attention.

Natural Sapphires can be any of the colours mentioned above, although Sapphire is commonly associated with the deep blue colour, which is usually enchanced due to heat-treating up to 1800C which brights out a slightly deeper colour, much the same as Tanzanite. So widespread is the practice of heat-treating Sapphire that is considered very rare to have an untreated gem, and these are normally supplied with a certificate to certify there is no evidence of treatment.

The colour of Sapphire is measured by three seperate catergories which are Hue, Saturation and Tone. Hue is essentially a value that determines the similarity or difference between one colour and another, and is more simply understood as the basic colour of a Sapphire. Saturation is slightly more complex but is on a simple level, the level of brightness or colour within the basic colour. This can be easily seen on photographs were saturation is adjusted where low saturation will look grey or washed out with high saturation being very vivid and more warm. Tone is similar to contrast in that is measures the difference between two extremes. In this case it is the brightness and darkness of the colour that is evaluated.

Sapphire can also be made synthetically through a process known as the Verneuil process where fine powder is melted and then crystalized into Corundum gemstones such as Sapphires or Rubies. This is increasing useful because of Sapphire’s industrial uses in watches or as electrical insulators. Sapphire is also incredibly hard at 9 on the moh scale (diamond is the hardest at 10), which makes it useful for creating scientific equiptment.

Tanzanite has gained wide popularity due to it’s refractive capabilites, in it’s rough state it is trichroic which essentially means that as light enters the stone it is split, or refracted, into three different sections of the visible light spectrum. This is changed during the heating procress (almost all Tanzanite is heat treated, as it is a brown colour in rough form), when it becomes dichroic therefore only refracting into two sections of the visible light spectrum, red and blue. This is what gives Tanzanite it’s deep blue colour and what enables the flashes of violet and red to be seen in the gemstone.

It is often quoted by Tanzanite companies that it is ‘rarer than ,’ while this may be true in terms of location, it is certainly not reflected in price. A flawless carat of Tanzanite will be close to $1,000 which is considerably less than a carat of ‘perfect’ diamond.

The main disadvantage of Tanzanite over something such as Sapphire is it’s relative softness. Ranked on the moh hardness scale at 6.5 compared to Sapphire at 9, it is more difficuilt to cut and more prone to breakage once set, therefore it must be looked after incredibly well. Tanzanite should also never be placed in an ultrasonic cleaner, although we have had cases where it has been placed in and been fine, it is not recommended and you are taking a risk of ruining the gem.

In conclusion, Tanzanite has been growing extrememely quickly in popularity and does look to continue this way, even if it is estimated we can only mine it for 15 more years.

A wedding ring becomes unique when it is personalised with a message and that is what you want them to be – a symbol of your special love for each other – a love that you know is no other’s but yours and to seal that love, rings that you know can be no other’s but yours. So go ahead and get those rings engraved – whether inside or outside is entirely up to you. Think about the message you want to put there – something that will stand the test of time. Don’t let anyone else make the choice for you – these are rings you have to live with for a lifetime.

A further option worth consideration is engraving the outside and embosing the inside, or vice-versa.  Embosing the inside does not hurt your finger but it does leave a mark on the skin when the ring is taken off, which is not a bad way to be reminded of something worth remembering.

Embosing the outside is  also a good option because it is quite rare and will set your ring out as unique.  A simple drawing embosed can look incredible and could be the difference between a good ring and a great ring.

Whichever option you choose it is the message that is the most important, pick something you want to see everyday and something that is a special to you as the ring itself.  Often dates such as the wedding day, or first date, if remembered,  are engraved.  A good idea for an embosing could be a simple stick drawing to a simple cartoon, or special symbol between the couple.

For wedding rings please

So should you reject all diamonds with some amount of fluorescence for your engagement rings? Not always, unless you find that there is a difference for the worse in real light. The advantage is, those with fluorescence are graded low by the grading labs so you might just be able to pick up a bargain. Just the fact that a diamond has it means it will be mentioned in its certification reports and that is enough to bring down the cost. The usual colours that fluoresce in a diamond are blue and yellow. You could ask the jeweller to show you examples and decide for yourself how they look.

Something worth considering is the fact that the intense colours you will see when flourescent diamonds are shown is due to the large amounts of UV light being directed at it.  In other words, in normal conditions under everyday UV radiation, from the sun for example, you will not see an intense colour but rather a ‘cloudy’ diamond.  This cloudiness has been likened to the look of vaseline smeared over the diamond, and is clearly undesirable.

If you want a diamond that is an intense or different colour then look towards either naturally coloured diamonds or the much cheaper heat-treated option.  As this way you can ensure you get a unique colour diamond engagement ring, without the dreaded cloudy effect that is all you get from heavily fluorescent diamonds in daylight.

Marquise:

It’s a very elegant and feminine cut and it flatters the hand that wears it on its finger. The marquise cut diamond is around twice the length as the width and the two ends taper gracefully to a point. It could be called boat-shaped and looks very elegant in a diamond ring. It can be used alone or with smaller diamonds to flank it. Remember that a marquise diamond needs to be the centre of attention so your design should be thought of accordingly.

There’s something you need to keep in mind when you are choosing a marquise cut diamond for your engagement ring. You need to ensure that it has a good rating where colour and clarity are concerned because in a diamond shape like this, flaws and imperfections may just be noticed so it needs to be of the best quality.  You also need to check if the angles of the cut are perfect because there can be times when the stone is not so well cut and a dark shadow appears at the bottom. This looks like a bow tie and this effect should be avoided so be careful when you buy. The marquise cut is one of the classic cuts and so has been popular for many years.

Asscher:

The name Asscher for this cut came about because this cut was first created by the renowned Asscher brothers of Amsterdam. They are famous in the world of diamonds because they have been associated with some of the world’s most famous diamonds like the Cullinan Diamond. The diamond with this cut is octagon-shaped – almost like a square with the edges rounded. When you look into the stone it has an effect of looking through many mirrors because of its parallel steps which make for refractive effects inside. The cut is patented and even today, the family insignia as well as a special identification number is put on each stone’s girdle and they can be seen only when magnified a lot.

If you choose an Asscher cut diamond for your engagement ring, you might want to ask the jeweller to magnify it for you so that you can see the number and the insignia in order to make sure it’s the real thing. So if you are very keen on a genuine Asscher cut, you should verify it and be sure. These cuts are usually in designs with just the single diamond so that its beauty can be appreciated without any distractions.