We all remember the Mohs hardness scale from high-school, but a gemstone's hardness is one part of what makes a great daily wear stone. Fracture toughness is equally important to consider. In this article, I will explain the differences between the two and how they should factor into your decision when deciding on the best stone for your engagement ring (or any ring you intend on wearing everyday).
What is the Mohs Hardness Scale?
The Mohs scale simply refers to how difficult it is to scratch the surface of a gemstone. Most popular engagement ring stones are very hard such as diamonds (10), sapphires and rubies (9), and emeralds (8).
Diamonds may be the hardest substance on Earth but they are not the toughest! Unfortunately, a gemstone's hardness does not always correlate to its toughness. An emerald is hard, but not very tough. Jade is very tough, but not terribly hard. So what does it mean to be tough?
What is Fracture Toughness?
The fracture toughness of a gemstone is determined by applying force onto a weak point in the stone (such as a chip or included area) until the stress causes the fracture to grow.
Toughness is very important to consider when you're going to be wearing a gemstone everyday because you will inevitably hit it on a hard countertop, drop it on a tile floor, or maybe even accidentally drop it down the garbage disposal!
Jadeite is perhaps the most interesting gemstone in regards to toughness because it is so tough it is hard to even fit it on the chart next to other gemstones. But it's not that hard! So while it may scratch moderately easily, actually breaking a piece of jadeite is extremely difficult. This is why there are many beautiful fine objects from Asia carved entirely out of jade that are hundreds of years old.
Recommended Engagement Gemstones
Fortunately, many gemstones popular for engagement rings are suitable for everyday wear. Our top picks are diamond, sapphire, ruby, alexandrite (chrysoberyl), and spinel.
Spinel is one of our favorite options because it is relatively inexpensive for its hardness, toughness, and rarity. Spinel is extremely rare and its most popular colors (red and blue) are more readily available in rubies and sapphires so it does not have a big commercial demand.
Some varieties such as jedi spinel and cobalt spinel are getting quite expensive, but there is a wide range of colors and price points. It's a truly beautiful, underrated gemstone well worth considering for your engagement ring.
Hard & Tough Picks from Our Store
Gemstones with Reservations
- Emerald (and Aquamarine)
- Opal
- Tourmaline
- Topaz
- Tanzanite
We only recommend these gemstones if you are prepared to baby your ring a bit. These stones are not suitable if you plan on wearing your ring all the time and wear jewelry that will rub up against your engagement ring.
For daily wear, we recommend a bezel setting for these stones.
