Considering the preciousness of diamonds, the International Diamond Grading System has laid a concept of the 4 Cs to determine the value of the stone. They are carat, cut, colour, and clarity. A carat is 0.2 grams and lesser the colour, more the value of the stone. The cut speaks of the precision and clarity is about the absence of inclusions and blemishes.
The value of diamond is all about the factors that you cannot see. Flawless diamonds are rare to find, but the transparency and brilliance are the aspects that decides the worth of a diamond along with the symmetry and polish.
Traditional diamond shapes are the pear, round, oval, emerald cut and marquise. Today, the stone is used in cushion, heart shaped and triangle shape even.
Rubies, emeralds and sapphires fall into the elite group of precious stones. Their rarity and beauty give them an edge over the other precious and semi-precious stones that are widely used in jewellery sets and have always been in consistent demand.
The hardness and toughness makes the stone highly durable and only second to diamond according to the Mohs Hardness Scale.
- Colour of the metal – Partial heat treatment is used to give the stone, the colour and transparency required. The brownish components are also removed through this method. Intense heat is applied to diffuse the colour causing elements and this also strengthens the colour of the stone. Oil and dyes are used to treat the surface reaching fissures and the colours come out stronger too. The cavities and fissures are filled with lead glass to improve the transparency of the stone.
- Cut – Rubies are available in various shapes and cutting styles in the market. They can range from ovals, cushions, round to the heart and the emerald cut. Round stones have a slight premium while the pears and marquises usually come with a discount. It is advisable to avoid stones that are shallow or overly deep.
- Colour – The colour of the stone comes in shades of vibrant green to bluish green. Pale emeralds are not genuine gems. Inclusions in this stone are pretty customary and rather expected. It is extremely rare to find emeralds with absolutely none eye-visible inclusions. These inclusions are often called ‘jardin’, or garden. These inclusions actually results in the even spreading of the light through the gem and is thus desirable. The fissures in the stone are often filled with paraffin, resins, oils and polymers.
- Cut – This is the only gen that has a certain cut named after it – the Emerald Cut. It is s square or rectangular outline step-cut with tapered corners. The facets present the inclusion panorama as a fascinating view. It is also cut in round, oval, pear and marquise.
- Colour – Being corundum mineral, a gem in known as ruby or sapphire depending on the metallic oxides of the stone that gives the gem its respective colour. Sapphires can be of any colour except red. The most sought after blue is known as the ‘cornflower’. ‘Padparadschas’ or lotus flower is pinkish-orange in colour and is the rarest. Inclusions in sapphires may result in a milky appearance. Chemical elements are often diffused to enhance or change colours.
- Cut – It is the traditional pear, oval, round, cushion and emerald cut that makes the cut of the sapphire. They are also carved and engraved in the current jewellery sets much like the way it used to be done during the Mughal Era of India.
[ Source :- Indiaparenting ]