I thought my diamond was forever?

If diamonds are the hardest gemstone, then how's it possible for a jeweler to tell me that my diamond now has a dangerous chip?

The truth is that even the very best diamonds can chip or break. They can also be split or cleaved.

How? Why?

As hard as they may be, diamonds still have "hard" and "soft" directions determined by their crystal structure. That's the essential reason why diamonds can be sawn and ground away with diamond dust. It's how they can eventually be shaped, cut and polished to perfection. It's tricky, but its what keeps us diamond cutters busy.

Diamonds are indeed the hardest mineral known, however they can be brittle. The Mohs hardness test – which ranks hardness from 1 (talc) to 10 (diamond) – is a "scratch test". Diamond can only be scratched by another diamond, it cannot be scratched by any lesser ranked minerals.

The difference between hardness and brittleness could* be illustrated by using a vice and a hammer.

If you put a diamond between the jaws of a vise and were able to apply steady pressure, then you could close the vise completely and when you reopened it the diamond would be safely imbedded in the steel. Its that resistant to pressure and much harder than the steel.

If you placed the diamond on top of the vise and smashed it with a hammer, there is no doubt in my mind that you would be well on your way to creating a nice little pile of diamond dust.

*Caution: DO NOT TRY THIS AT HOME. TRUST ME.

I must also tell you that wherever there is an edge, there's always risk and danger!

The sharper (or more acute) the angle of any edge, regardless of how hard it is, the more susceptible it is to damage. Think about a razor's-edge as opposed to the edge of an axe. Both are steel, but the razor edge is much easier to nick or break.

That’s the primary reason cutters put a "girdle" or protective edge around the circumference of polished diamonds. It turns an otherwise acute edge into two blunt angles, thereby reducing the risk of chipping.

It is common practice for diamond setters to place any thin girdle edges, or knife-edges or small chips underneath a prong. The idea is to add protection to a weak spot as well as to hide unsightly blemishes. It's most often a good practice.

The downside is that pre-existing flaws may not be uncovered until much later, and sometimes they'll "grow" bigger because the prong itself – acting as a wedge – has caused further damage.

There is a silver-lining in learning that your diamond has sustained damage. Now is the best time to find out if it should be repaired just to fix the damage, or maybe it's worth fully recutting to better standards which quite possibly will make it more durable and much prettier and more valuable.