What will scratch a diamond? Well, only another diamond. Diamonds are the hardest of all gemstones registering a 10 on the Moh’s Scale of Hardness. What can a diamond scratch? Well, only another diamond plus all the other gemstones in the mineral world. What is the Moh’s Scale of Hardness and what do gemologists mean when we say a gemstone’s hardness?
The Moh’s scale of hardness was developed in 1822 by Frederich Mohs. This scale is a chart of relative hardness of the various minerals with 1 being the softest up to 10, the hardest. Succinctly put, Moh’s scale is a measure of the relative hardness and resistance to scratching or abrasion between minerals. Thus, the only thing that can scratch a diamond is another diamond. Now, please note that a hard gem or mineral is not automatically tough or durable.
A mineral’s toughness is its ability to resist being fractured. Toughness is extremely important to many jewelry wearers because if the gemstone is purchased to be worn on a daily basis, it may become damaged either by impact or by being chipped and that makes it more fragile. A tough mineral will resist fractures. A soft mineral will not.
Usually diamonds are very hard, but they can certainly chip and fracture in normal day to day wear and tear. For instance, if a mineral crystal is formed in a certain way, it can make it prone to chipping or fracturing. Another way a gemstone can be more prone to chipping or fracturing is by how it is cut. A diamond that has many facets may be more prone to chipping, while a diamond that is cut with less facets, may be less prone.
When buying jewelry, a jewelry designer must know the hardness of stones because certain stones are too soft to say, be worn as a ring. A consumer will not see a lot of apatite in rings because this beautiful gemstone is only a 5 on Moh’s scale. It comes in beautiful shades of blue and green that can rival an aquamarine, it is still not hard enough to withstand, say a ring finger inadvertently knocked on a car door or a kitchen counter.
What does this all have to do with a jewelry designer and a buyer? Well, as a designer, I have the obligation to educate my customers about their options and to help make a good choice. This begins knowing the gemstone’s number on the Moh’s scale of Hardness and how tough and durable a gemstone is compared to others.
Check back for an upcoming piece on sapphires and spinels and where they range on the Moh’s Scale of Hardness.