Abstract: To those with some knowledge of cut diamonds, the measure of an excellent cut diamond is in the grading of the 4 Cs, as in Color, Clarity, Cut & Carat. To the uninitiated, the 4 Cs may simply means Crazy Costly Carbon Crystals.
Yes, a cut diamond consists of carbon crystals. It is about the only gemstone that is made up of only one element, that is, crystalline carbon. A diamond is 99.95 % pure carbon while the other remaining part may consist of very minute amount of other trace elements.
Graphite is also made up of the carbon element, though the percentage of carbon is much lower.
In science, allotrope means that an element can exist in different physical forms. Hence, diamond and graphite are allotropes of carbon.
The difference between these two elements is in the way the carbon atoms are bonded together. Diamond is bounded in a four-cornered tetrahedral lattice arrangement, while graphite is bonded in sheets of a six-sided lattice. Hence, diamond is the hardest mineral on earth while graphite can be sheared off easily as in the lead of a pencil.
Diamonds, as carbon crystals may not be rare, but well cut gem-quality diamonds are indeed rare. They are formed beneath the Earth’s mantle at depths of between 150 to 250 km under high heat and pressure. The age of natural diamonds ranges between 1 billion to 3.5 billion years. And they are brought up to the surface of the earth through volcanic eruptions and are then deposited in igneous rocks known as kimberlites.
One of the most important factor that accounts for this ‘crazy costly’ crystals is that it can be well polished to an adamantine lustre (ie, radiance and brilliance) because of its unusual hardness.
In 1948 de Beers, the leading diamond corporation, came out with the iconic tagline ‘A Diamond Is Forever’ and since then it has become one of the most recognizable slogans of all times, as it captures the heart of a woman in love.
A recently concluded sale of an emerald cut diamond, weighing 8.1 carat (or 1.62 gm, as 1 carat is equal to 0.2gm) is done for more than US$400,000. And it has a width and length of about 12 x 10mm.
Now, that is crazy costly, but to the buyer this investment grade diamond is well worth the price.