India, Oct. 16 -- It can feel hard to answer the question "Is that the real thing", while wearing a lab-grown diamond. Technically, it has the chemical composition of a diamond. Visually, it sparkles. So, why the hesitation?

Because we know the story; and the story marks the difference.

A lab-grown diamond can be made in days or weeks, depending on the processes used. These processes include the use of immense pressure and temperature, and the use of chemicals, to turn a seed (a fragment of an earlier natural or lab-grown diamond) into a fresh stone.

What story does this crystallised carbon tell?

One cannot say: "Oh yes, this is from Canada, where it lay in the earth for hundreds of millions of years, as a whole planet took shape arou...