Close-up image of Emerald stones Close-up image of Emerald stones

The Mohs
Hardness Scale

Background

All gemstones are rated for hardness and scratch ability on a physical scale known as the Mohs Hardness Scale. The softest mineral on earth is Talc, rated No 1 on Mohs scale and the hardest is a Diamond, rated No 10.

In order for a gemstone to be considered hard and scratch resistant enough to be practically incorporated into jewellery, the minimum rating on Mohs needs to be 6 or above. 

Obviously, some jewellery categories are more prone to wear than others, Rings being the most likely to be exposed to wear and knocks, compared to earrings or pendants.

We have indicated where each of the gems described above sits on Mohs scale. Hopefully this will help when it comes to enjoying your Stephen Webster pieces while carrying out everyday pursuits.

Example of diamond at Mohs hardness 10 — hardest gemstone on the scale Example of diamond at Mohs hardness 10 — hardest gemstone on the scale

10 | The Only Example: Diamond

Come and have a go if you think you’re hard enough: No thanks.

Ruby at Mohs hardness 9 showing high durability typical of corundum gemstones Ruby at Mohs hardness 9 showing high durability typical of corundum gemstones

9 | Example: Ruby

Corundum’s in general are hard enough to take almost all the knocks life can throw. The original gem choice for engagement rings. Rubies and Sapphire are resilient rocks, many outlasting marriages, and the rigours of life. 

Topaz gemstone representing Mohs hardness 8-8.5 and practical jewellery durability Topaz gemstone representing Mohs hardness 8-8.5 and practical jewellery durability

8-8.5 | Example: Topaz

Not the hardest nut but tough enough to withstand a plethora of other materials. Like all gems a sharp knock or being dropped from a great height onto a hard surface can result in tears. Even a diamond has a cleavage plane if caught unawares. Avoiding the obvious occupational hazards such as hard labour or brick laying, Topaz can come out most days that end in a ‘Y’. 

Tourmaline gemstone at Mohs hardness 7-7.5 — suitable for everyday wear with some care Tourmaline gemstone at Mohs hardness 7-7.5 — suitable for everyday wear with some care

7-7.5 | Example: Tourmaline

Sitting right on the fence between everyday wear and occasion, Tourmaline is tough enough, but still should be worn with an element of awareness with regard to exposure to excesses force, such as when gardening or contact sports involving helmets or requiring bats. Other than these unlikely scenarios, Tourmaline is a gem to be enjoyed. 

Tanzanite at Mohs hardness 6-6.5 — advised for protective settings in rings and fine jewellery Tanzanite at Mohs hardness 6-6.5 — advised for protective settings in rings and fine jewellery

6-6.5 | Example: Tanzanite

We would not recommend this beautiful gem for everyday wear. The stone should be set in a way that offers as much protection as possible. Bezel settings are a way of protecting the most vulnerable edges of the stone. We recommend wearing the gem to cocktail parties, around the pool at fabulous resorts and almost all (except for the most rowdy) dinners for two or more.