Why is the MOHS scale important?

Posted on the 30th November -0001

Why do gemmologists use the MOHS scale of hardness?

What is a MOHS scale?

It is the scale used to help identify minerals based on their hardness. The gemstone industry have used this scale since Friedrich Mohs developed it in 1812.

1-10 (10 being the hardest)

10: Diamond

9: Corundum

8: Topaz

7: Quartz

6: Orthoclase

5: Apatite

4: Fluorite

3: Calcite

2: Gypsum

1: Talc

Although the MOHS scale does indicate a stone hardness and overall durability, it is not linear e.g. the difference between Corundum (9) and Diamond (10) reflects a hardness increase of more than 300%. 

There are intricacies of the different gemstones which Holts Gems take into account when testing, using or valuing stones, for example, some gemstones have very good hardness but poor toughness (ability to withstand chipping/cracking). 

Jade, for instance, has excellent toughness but poor hardness - this allows it to be carved easily and means it can withstand being struck.

In selecting gemstones for our bespoke customers, we take into account the recipients lifestyle and proposed use of the jewellery item in order to select the right gemstone. Our qualified gemmologists are passionate about gemstones, something which is clear from the moment you step into Holts Gems.