For a long time, diamonds have been the most popular stones to put on an engagement ring, but in recent times, that is starting to change. Blue Sapphire is making a comeback, and that means your engagement ring options just increased exponentially. This guide goes over the most important things you need to know about blue sapphire before you go out and shop for a non-traditional engagement ring.

The History of the Blue Sapphire

Blue sapphires in engagement rings first started coming back into style when Prince William used his mother’s—the late Princess Diana’s—13-carat blue sapphire ring to propose to Kate Middleton. But the historical use of blue sapphires dates back much further than that.

In the middle ages, clergymen and high priests used sapphire in rings to symbolize the heavens and royalty used it as a symbol of knowledge, wisdom, and divine blessing. The Ancient Persians believed that the world rested on a blue sapphire, and the color of the sky was a result of the sapphire’s reflection. In Ancient Greece and Rome, sapphire was believed to provide protection from jealousy and destruction.

In recent days, it is an increasingly popular choice for couples who wish to show that their relationship is built on faithfulness and sincerity.

Blue Sapphires: The Basics

On the Mohs scale of mineral hardness, sapphire comes in at a 9, putting it second only to diamonds (10). This is one reason why blue sapphires in engagement rings are growing in popularity: they provide a pop of color to give a ring its own unique feel while still providing the durability that diamonds do at a significantly lower price.


For sapphires and other colored gemstones, color is the “c” that is most important to look at. Whether a sapphire has good color is determined by its hue, tone, and saturation. If a stone does not have the right combination of these three things, it may appear as dull, colorless, and gray. The blue sapphire’s hue is measured according to the following:

  • Strong green
  • Slight green
  • Blue
  • Slight purple
  • Strong purple

The “bluer” a sapphire appears, the more valuable it is. The ideal color for blue sapphires is known as “cornflower blue,” because the cornflower is a genuinely blue flower, unlike other flowers that are described as blue but are purple.

The tone of the sapphire is how light or dark the color is and the saturation is how vibrant the color is. Scales that determine tone range from very light to very dark, while scales that determine vibrancy range from dull to vivid. For tone, the best blue sapphires are in the medium to dark range, and for vibrancy, the closer to vivid you can get the better.


While the clarity of a diamond is paramount, the clarity of sapphires is relatively unimportant. This is because you can very rarely find sapphires without any imperfections. In fact, if there is a sapphire that is flawless, most gemologists will suspect that the gem is a fake, or at least treated, which can significantly alter the value and price of the gem.

For diamonds, gemologists use up to 10x magnification when inspecting it for imperfections. For sapphires, however, the only thing gemologists are concerned about is the imperfections that are visible to the human eye. The cleaner the stone is to the human eye, the more valuable—and more expensive—it is.


Unlike diamonds, sapphires do not come in standardized cuts. Diamonds are individually cut to show off the diamond’s brilliance and fire, but with sapphires, you must rely on the gem cutter’s judgment when it comes to maximizing each sapphire’s exclusive mixture of color and clarity.

A well-cut sapphire, for example, would be symmetrical and would reflect light in such a way as to make the gem look shinier.


The carat weight of a sapphire is different than the carat weight of a diamond because both stones have different densities. Sapphires are heavier than diamonds, which means that a one carat sapphire will be smaller than a one carat diamond. That is why sapphires are usually measured by their diameter in millimeters. Typically, a one carat sapphire has a diameter that measures about 6 millimeters across.

Here are a few more things you should know before you go to jewelry stores looking for your blue sapphire engagement ring:

  • Only shop at jewelry retailers that have established reputations
  • The price of the sapphire will often tell you if the gems have been treated or not (the gems that have not been treated are more valuable and expensive)

Blue Sapphire is making a comeback, and if you’re looking for an engagement ring that has a little flare to it, it is important that you know the differences between shopping for diamonds and shopping for sapphire. Knowing the information in this guide will help you do just that.

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