Best gemstones for an engagement ring

While there are hundreds of different gemstones found across the world, only a select few stones are suitable for an engagement ring. 

Engagement rings are worn everyday, so the stone that's featured needs to be durable enough to withstand the accidental knock or scratch. This is where the Moh's Scale of Hardness comes in. 

Hardness refers to a gem's resistance to scratching. Invented in 1812 by mineralogist, Freidrich Mohs, the 'Moh's Scale of Hardness' ranked 10 common minerals in order of hardness, a.k.a their ability to scratch and be scratched. 

Talc, which is commonly found in powered form, ranked #1 as the least hard, while diamond ranked #10, making it the hardest mineral in the world. Only a diamond can scratch a diamond, but talc can be scratched by every mineral ranked above it. 

Moh's scale of hardness

The scale helps us determine which gemstones are suitable for everyday wear. Generally, engagement rings should feature stones that sit no less than 8 on the scale. So let's see which stones make the cut!

Gemstone Hardness level
Diamond 10
Synthetic Moissanite  9.25
Ruby 9
Sapphire 9
Alexandrite 8.5
Chrysoberyl 8.5
Yttrium aluminium garnet 8.5
Taafeite 8-8.5
Spinel 8
Topaz  8


The scale is exponential, not linear. For example, a Moissanite measures a 9.25, but that doesn't mean it's 0.75 points less than a diamond. The below graph shows just how hard a diamond is compared to its counterparts.

Mohs scale of hardness

So, a diamond isn't the only option for an engagement ring. Our personal pick as a runner up would have to be a sapphire. What would yours be?