For centuries, scientists have tried to understand how molluscs produce such perfect objects. “We humans, with all our access to technology, can’t make something with a nanoscale architecture as intricate as a pearl,” said Professor Robert Hovden, a materials science and engineering expert. “So, we can learn a lot by studying how pearls go from disordered nothingness to this remarkably symmetrical structure.”
As a pearl is built, its symmetry edges towards perfection, coaxing order from unpredictable layers of nacre, the durable organic-inorganic composite that gives it its pearlescent sheen. The process begins when nacre covers a shard of aragonite that surrounds an organic centre. The layers of nacre, which comprise more than 90 per cent of a pearl’s volume, become progressively thinner and more closely matched as they grow outward from the comparatively clumsily built centre.
By adjusting the thickness of each layer of nacre, molluscs maintain symmetry...