- Category: Gemstones by the Month
Diamond: April's gemstone
Diamonds are a wonder of nature. Their cold sparkle has held us spell-bound for centuries - with myths of romance, power, greed, and magic. Ancient Hindus, finding diamonds after thunderstorms, believed they were created by lightning bolts. Today, the diamond is a symbol of enduring love.
What are diamonds?
Diamonds are the rich cousin of graphite, both crystalline forms of pure carbon. The difference in their properties is because of the way the carbon atoms are bonded together. In graphite, the atoms are arranged in sheets that easily slide past each other, making them ideal as lubricants. Diamond crystals, are a tight-fisted network of carbon atoms securely held in four directions creating the hardest naturally-occurring substance.
Until recently De Beers controlled the entire world’s diamonds. By stockpiling tons at a time, they greatly increased the value of a relatively-common crystallized rock.
However, it’s now possible to artificially grow diamonds, amazingly the same way they are formed over millions of years. Using high-pressure in a chamber the size of a washing machine, a tiny sliver of natural diamond is bathed in a molten solution of graphite and a metal-based catalyst at 1,500 degrees C. Slowly, carbon precipitates onto the diamond seed crystal, growing to 2.8-carats in a few days. This can then be cut and polished to give a gem larger than 1.5 carats.
To say these cultured stones are not real diamond is false. Chemically they’re identical to mined diamonds, but they do have different growth patterns and a lack of inclusions that would draw suspicion to a qualified jeweller. However, impurities in a natural diamond are regarded as flaws - a lack of inclusions is actually a good thing. For a jeweller to tell for sure a diamond is natural, De Beers has designed a machine for around £10,000.
A much cheaper way of making a stone that looks like diamond was created by Russian scientists. Cubic Zirconia is a dense clear material through which laser light can be reflected. When melted at high-temperature and an incredibly-high electrical current sent through it - the compound crystallizes, forming chunks similar to rough diamonds, which are then cut and polished.
Genuine or manmade
Using the naked eye, even a trained jeweller can’t detect the difference between good cubic zirconia, genuine, or cultured diamonds. And even diamond experts have been fooled between cubic zirconia and a five-million-dollar diamond. All are fully faceted, cut and polished the same.