Moh's Hardness Scale

When looking for gemstones for jewellery, engagement rings or othewise, you may see or hear your jeweller or your jewellers website mention Moh’s Hardness Scale. 

What is the Moh’s Hardness Scale?

The Moh’s Hardness Scale is a relative system based on 10 different minerals and gemstones used as a reference for how easily specific gemstones scratch. 1 is the easiest to scratch and a 10 is the most difficult. Diamonds are a 10. 

The concept is if you have a stone of unknown hardness, and reference mineral #5 can scratch it, then the hardness of your gem is less than or equal to a Mohs hardness of 5. Similarly, if your gem cannot be scratched by reference mineral #5, then its hardness is greater than or equal to a Mohs hardness of 5.

What Hardness is Preferred for Everyday Wear?

Moh’s Scale is the most commonly used system to rate the hardness of gemstones.  Anything with a rating of or above 7 is what is most commonly used in jewellery today.

Diamonds are the hardest minerals on earth; they are 4-5 times harder than corundum, the family of sapphires and rubies, which are rated a 9 on the scale. Understandably, this is why diamonds are so desirable for engagement rings.

High quality loose diamonds selected by Larsen Jewellery

Moh's Hardness Scale

 HardnessMineralComparison
 10Diamond 
 9Corundum (Sapphire & Ruby) 
 8Topaz, Emerald, AquamarineMasonry drill bit (8.5) 
7Quartz (Amethyst, Citrine and Agate) 
6Orthoclase Nail (6.5)
5Apatite Knife (5.5)
4Flurospar 
3Calcite Copper coin (3.5)
2Gypsum Fingernail (2.5)
1Talc 
High quality loose diamonds selected by Larsen Jewellery

Talk to an expert

Sydney: (02) 9223 2006
Melbourne: (03) 9662 3005
Brisbane: (07) 3051 0839

Holiday Deadlines

Make your wishlist sparkle and order before these dates to receive your jewellery pieces in time for Christmas Day*

Bespoke Engagement Rings & Custom Jewellery: Depends on design – Ask us!
Bespoke Diamond Set Wedding Rings: 25 November
Bespoke Plain Wedding Rings (no diamonds): 7 December
All Ready-To-Wear Collections (to be posted): 20 December
All Ready-To-Wear Collections (in-studio): 24 December

Miss a deadline? We may still be able to help. Reach out to our studio to see if we can work a Christmas miracle for you.

*Time frames may vary between studios depending on the number of pre-Christmas orders received. To avoid disappointment please contact your nearest studio for more details. A deposit must be paid and the design and gemstones confirmed by each deadline date respectively.

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