When it comes to modern wedding and engagement rings, having a gemstone is pretty commonplace. Although there are a myriad of details that can make or break the lifespan of your sentimental jewellery, selecting things like aesthetics and price may be the only things on your mind. Still, in the world of gemstones, it's the finer details that you need to be aware of if you want to pass your pieces on to future generations.

Colour

Because most popular gemstones are organically produced, the range of colour varies drastically; the number of graded colour diamonds alone is usually in the range of 200-300 shades. These differences all come down to three factors, Base colour, the intensity of colour and secondary colour; coloured diamonds have 12 base colours, red, yellow, orange, green, blue, pink, purple, brown, violet and grey.

These base colours also come in different hues; most of these base colours are then graded with 9 levels of intensity, from faint to fancy vivid. The in-between levels are fancy intense, fancy deep, fancy dark, fancy, fancy light, light and very light. However, not all colours are available in the entire intensity range, with red and yellow not naturally produced in light variations.

Finally, most precious stones comprise more than one colour, with a dominant colour and one or two more colour variations, e.g. an orange-red diamond.

Cut

The cut of your stone (Or shape) is often determined by the stone itself, with certain gemstones favouring varying degrees of severity. For example, an opal and a sapphire require two vastly different cuts to highlight their unique beauty, with opal selecting a smooth, rounded cut to show off the rich speckled look and a sapphire showcasing its beauty with a sharper brilliant-cut that allows it to glitter in the light.

The stone's symmetry also determines the cut required; a good stone cutter will be able to work with the organic shape of the stone to create a beautiful and unique look for your ring.

Clarity

Clarity describes the flaws in the stone, from cracks on the surface to inclusions and air bubbles deeper into the rock. The higher the clarity of the stone, the higher the price tag. However, most stones' flaws are only visible through a microscope, and these unique details can act as a distinction for that specific stone and ensure that no two organic stones are alike!

The real question is, do I need a perfect stone? And the honest answer is no because most of the flaws in the stone that would reduce clarity are microscopic; having what is termed as an "eye clean" stone will give you your dream ring for a substantial drop in price tag.

Luster

The luster of a stone is the surface appearance, its shine, lack of flaws and how the light can refract through the stone. A great example of this is the chatoyancy optical effect, or Cat-eye effect, that gives specific stones such as a chrysoberyl cat's eye. This stone gets its signature cat's eye from the light refracting through the stone; the smoother the surface, the better the effect.

Certain cuts will maximise the luster and shine of a stone, with stones like diamonds, ruby, sapphire and emeralds being most popularly cut with sharper, drastic angles to give the light reflection a glittery and dynamic look. The luster of a stone is also vital for adequately identifying the gem at hand; this will play a part in how an insurance company will value your ring. Specific stones reflect light in particular ways, and this distinction is how you know if you've said yes to a diamond or cubic zirconia.

Durability

For jewellery, durability is vital; you'll be wearing this stone on your hand, so it's going to have to take a lot of battering; no matter how careful you are, digging through a handbag can cause some severe damage to a fragile stone. One of the big reasons diamond is the most common choice for engagement rings is because it's one the hardest substances in the world, rating 10/10 on the Mohs Hardness Scale; you could run it over with a car, and the only damage would be to the metal ring.

However, if a diamond isn't your best friend, you might be looking at other more unique options. Some of the more durable gemstones are sapphire, emerald, ruby, aquamarine, spinel, alexandrite, topaz; these are beautiful and colourful gems that can hold their own against the regular wear and tear of life. Gemstones of a 7.5/10 on the Mohs Hardness Scale and above make the best engagement ring centre stones; with sapphire and ruby following closely behind diamond with a 9/10, followed by alexandrite with an 8.5/10, spinel and topaz with 8/10, and finally aquamarine and emerald ranking 7.5/10 on the Mohs Hardness scale.

Stone to be avoided in traditional minimalist settings are amethyst, opal, pearl, tanzanite and morganite; while each are beautiful, they run the risk of cracking, chipping, staining or even shattering with regular wear and tear. However, while they may not suit the starring role in an engagement ring, they can make gorgeous accents provided the style of ring is protective to the stone, which means you won't be able to have a minimalist pearl engagement ring. Still, a white cabochon sapphire with pearl accents will make a breathtaking alternative.

Country Of Origin

Particular countries of origin command higher prices than others.  Gem mines with long traditions in producing important gemstones are most sought after.  Examples are Kashmir blue sapphires, Colombian green emeralds or Burmese red rubies. But, this does not mean that all gemstones from premium origins are the best or top colour quality. In fact, some rubies from Tanzania or Madagascar can beat a lot of the Burma rubies. Yet, due to their country of origin, they will almost always sell at a discount.

Carat

One of the first things you think of when you hear the word diamond is the carat; it's well known that the higher the carat, the higher the price tag, but many don't know what the carat is. Carat is not the size but the mass of the stone; two stones could be the same size right down to the micro-millimetre but have different carat weights because of the mass and pressure of the stone. Gemstone sizes are measured with carat weight, which equals 0.2 grams or 100 points per carat. Because carat is measured with mass and density, there can be a vast size difference between equally graded stones; rubies are denser than diamonds, so a 1-carat diamond will look bigger than a 1-carat ruby.

To maximise your stone to carat ratio, look for a gem that has a large crown when compared to its tail (If you think of a cartoon diamond, the grown is the large, dramatic top, and the tail is the smaller tapered bottom), this will save you money but will give your stone a dramatic, large appearance.

Cost

The cost is a pretty huge factor when choosing a stone for your wedding ring set; it's also the hardest to predict without speaking to a jeweller. This is because so many factors play a role in the cost of each stone, as listed above. To ensure you get the best value for money regarding your ring, meet with a professional and do your research!

- Gráinne