What Are Diamonds and Why Do They Sparkle?
Diamonds, with their mesmerizing bursts of light and unparalleled beauty, have captured the human imagination for centuries. Yet the cut and polished diamonds you see, for example, in engagement rings, bear little resemblance to their original form.
Diamond, the hardest known substance, is made entirely of carbon. Diamonds form over billions of years and as much as 120 miles below the Earth’s surface, where unfathomable temperature and pressure rearrange carbon atoms into a crystalline structure. Volcanic eruptions then act as an elevator, lifting the diamond-bearing material closer to the Earth’s surface. Some of the material gets washed down ancient riverbeds.
Turning rough diamonds into “Wow!” diamonds
When mined from the earth or the ancient riverbeds, rough diamonds look like pieces of ordinary molten glass. The raw material holds remarkable, natural optical qualities. But it takes highly specialized skill, scientific knowledge, and tools to turn rough diamonds into the sought-after, scintillating gemstones that are universally treasured. It wasn’t until the mid-1700s that man’s understanding of the science of optics and the art of diamond cutting converged. In 1919, master gem cutter and mathematician Marcel Tolkowsky established the 58-facet standard and today’s most widely accepted proportions for an ideal cut round diamond.
By the way, if you are in the market for an engagement ring, take some advice from someone who has been buying diamonds from the cutters in Antwerp, Tel Aviv and Mumbai for 25 years. Buy a 58-facet diamond and you will have a diamond which will be more valuable over time, worldwide. A diamond that has been deliberately cut with an odd number of facets – which is a marketing gimmick used by some jewelers – will prove to be very difficult to trade in or resell in the future.
Why do diamonds sparkle?
A diamond’s sparkle is caused by light reflecting or sparkling off of the crown facets of the diamond – the table, upper girdle, bezel and star facets. These flickers or flashes of light are called scintillation. Fire describes the diamond’s ability to disperse the different colors of the light spectrum, while brilliance describes the diamond’s return of white light to the eye. The more light a diamond reflects back to your eye, the more scintillation, dispersion and brilliance it has.
The cut of a diamond determines how much scintillation, dispersion and brilliance is present. A diamond cut too deeply will allow light to escape out of the side of the diamond. A diamond cut too shallow will allow light to escape out of the bottom of the diamond. Other major or minor symmetry issues may also result in an optically inefficient diamond.
Whatever your definition of affordable engagement rings is, knowing how to evaluate diamonds will help ensure you get the finest quality diamond for your money.