DIAMONDS & COLOURED GEMSTONES
WHAT TO LOOK FOR WHEN BUYING A DIAMOND
Set out by the GIA – Gemological Institute of America, The 4C'S diamond grading system refers to the Colour, Clarity, Cut and Carat weight.
When it comes to colour, the less colour you can see, the more valuable a diamond becomes. The GIA scale is the industry standard grading from colourless, D, to light colour or yellow or brown, Z.
On the colour scale, D-F is colourless, G-J near colourless, K-M faint, N-R very light, and S-Z light.
The slight difference in colour whilst being subtle, can make all the difference to the price of a diamond.
Every diamond is unique and often contain inclusions (internal) or blemishes (external). It is the absence of these that makes a diamond incredibly rare and valuable. Most diamonds will have a birthmark of sort, and it is the GIA diamond grading system that assigns a clarity grade from Flawless (FL) to those with quite obvious inclusions (I3).
Most commonly found on the market are diamonds graded Very slightly Included (VS) or Slightly Included (SI).
The cut of a diamond is often considered the most important of the 4 C's. You may hear the phrase “cut is King”. It refers not to the outline shape of a stone, but the way in which the facets are arranged; the quality of which creates a diamond's brilliance, fire and sparkle. Sparkle, or Scintillation, refers to the pattern of light and dark areas of reflections within a diamond. These are appearance-based aspects.
The design and craftsmanship are also factored in to a diamond's cut grade. A diamonds proportions- its weight ratio and its effect on its durability, and the symmetry and polish of facet arrangement.
The GIA cut scale ranges Excellent, Very Good, Good, Fair, Poor.
Whilst there is a correlation, the CARAT refers to weight, and not a diamond's actual size. A 0.50 carat diamond, or 50 pointer, could vary in dimensions from one to another with the same carat weight. This weight-to-size ratio is known as a diamond's 'spread'.
WHERE DO I SOURCE MY DIAMONDS?
Hand picked by reputable sources from London's jewellery quarter, Hatton Garden. I ensure the gemstones I buy are GIA registered and from a conflict-free background.
WHAT DO THEY MEAN?
Gemstones have been associated historically to have different healing properties; at times a symbol of wealth; to mark a moment in history- be it a ruby wedding anniversary, or the birth/death of a loved one.
Amethyst for example is a Quartz. It can be found in a pale lilac or a deep purple, and measures a 7 on the Mohs hardness scale. The richer the colour, the more valuable the stone. It is the Birthstone for February. Its crystal healing properties have been thought effective towards insomnia and headaches.
WHAT COLOURS CAN BE FOUND?
Gemstones come in all different colours and range in hardness on the Mohs scale. Most can be cut and polished to the classic brilliant [or Tolkosky] round shape, or to a more fancy shape, including pear and emerald.
Coloured stones can be altered or enhanced with dying and heat treatment. Gemstones that are commonly found to be heart treated include Aquamarine, Citrine and Tourmaline, to name a few.
It is also worth keeping in mind that heat treated stones to enhance its colour, can often be altered or lost altogether when re-heated. It is advised that any sizing in the future requires the stone to be removed beforehand.
A gemstone's value can increase dramatically depending on its colour too. For example, you can expect to pay around 3x as much for a delicious pink diamond from the Argyle mine in western Australia as a clear diamond.