Are Montana Sapphires Good for Engagement Rings?

Montana Sapphires Durability  

     Some people have asked whether Montana sapphires are good for engagement rings. It is an important question, and so it deserves a thoughtful answer. It is a topic that is of great interest to a great many people. The comments that follow will be helpful.

     One of the most essential attributes of sapphire to consider in answering the question is durability. Will it retain its bright appearance after years of wear? How does sapphires’ durability compare with the durability of other potential engagement gemstones?  

     Durability is primarily a function of hardness, which, in this case, is defined as a crystal’s ability to resist abrasion. If a gemstone is relatively soft, it will have relatively low abrasion resistance; its surface will become pot-marked and scratched. When that happens, its finely polished surfaces become compromised, and light that would otherwise have entered the stone is now reflected off the surfaces and causes the stone to appear dull and lifeless.

    Fortunately, sapphire, whether from Montana or anywhere else, has an excellent hardness rating. It is harder than any other natural gemstone except diamond. That means it is more resistant to becoming abraded than any other gemstone except diamond.  

Montana Sapphire Hardness on Mohs Scale     

How hard is hard? If it is slightly harder than other gemstones, the comments above lose significance and are not very meaningful. To shed light on this question, we can utilize a popular hardness scale that many people are familiar with. It is called the Mohs scale. The Mohs scale rates minerals on a scale of 1 through 10. Diamond is 10. Sapphire is 9. Gemstones like amethyst and citrine are gemstone varieties of a mineral called quartz. Quartz is seven on the Mohs scale.

Quartz is a prevalent mineral. Much of the dust in the air and dirt beneath our feet consists of quartz. This is significant because it means that any gemstone that ranks seven or less on the Mohs scale is more vulnerable to abrasion than gemstones that rank eight and above on the Mohs scale. It is impossible to scratch a mineral with a hardness of 7+ with a mineral of -7. Sapphire cannot be scratched by the most common form of dust, which is quartz.  The Mohs scale is helpful if one is only interested in knowing relative hardness.

The Knoop Scale

There is a better scale to measure “how much more hard” hardness. It is called the Knoop scale. Its values are logarithmic. Quartz on the Knoop scale has a hardness value of 820. Sapphire value is 2100. Sapphire is nearly 3X harder than quartz. The values cited reflect the amount of energy it takes to make an indentation in any given material with a diamond point.


On the basis of hardness considerations, we can give a thumbs up to the question as to whether Montana sapphire is good for engagement rings. However, hardness is one of many factors to consider. There are many others. Color, refractive index, value retention, availability, and costs are other variables that not only bear on the question but may be just as critical in providing a complete answer to this crucial question of choosing center stones for engagement rings. Each of these other variables deserves extensive treatment and so should be dealt with separately.

Written by Arlan Abel FGA  100% human-generated content