The round brilliant, the shape behind most engagement rings sold today, feels like an obvious choice. Simple, symmetrical, endlessly sparkly. What most buyers do not realise is that this exact shape took roughly three hundred years of trial and error to get right.
It started with a cardinal
The story usually begins in the 17th century with the Mazarin cut, named after a French cardinal, which introduced 17 facets in an early attempt to bring out more brilliance in a stone. It was a genuine step forward, but still a long way from anything resembling the sparkle we associate with diamonds today.
Then came the Peruzzi refinement
Later, Italian cutter Vincenzo Peruzzi pushed the design further, increasing the facet count and improving how light moved through the stone. This period laid the groundwork for what eventually became known as the Old European cut, the direct ancestor of the round brilliant, still prized by collectors today for its warmer, softer glow compared to modern cutting.
The maths finally caught up
The real breakthrough did not arrive until 1919, when Belgian diamond cutter Marcel Tolkowsky, from a family of diamond cutters himself, published a thesis calculating the precise angles and proportions needed to maximise both brilliance and fire. His calculations gave the world the standard round brilliant we know today, a design built on nearly three centuries of earlier cutters slowly working out what actually made a diamond sparkle.
Why this history actually matters when you buy
Modern cut grading exists because of exactly this journey. A diamond cut to Tolkowsky's proportions returns far more light to the eye than an Old European or earlier cut ever could, which is exactly why cut quality affects a stone's brilliance as much as its carat weight does. Two diamonds of identical size can look completely different depending on how closely their proportions follow this centuries-old formula.
A cut worth appreciating properly
Next time you look at a round brilliant diamond, it is worth remembering that its sparkle is not an accident; it is the result of three hundred years of cutters slowly solving the same problem.
Visit Azzallure to see round brilliant diamonds cut to genuinely maximise their brilliance, built on centuries of getting it right.