A sapphire is a naturally formed precious gemstone known for its striking blue color. Although blue is most popular, sapphires also come in pink, purple, yellow, green, white and more. Made from the mineral corundum, sapphires are extremely hard, scoring a 9 on the Mohs scale of mineral hardness, second only to diamonds which come in at a perfect 10. Historically, sapphires have been used in jewelry for centuries and have been popular among royalty and the upper class.

Choosing the best diamond is all about the 4 Cs (cut, color, clarity, carat). The same is true for sapphires with a few key differences. Sapphires only need to appear “eye-clean”, which means they have no inclusions visible to the naked eye. Sapphires are also heavier than diamonds, so they often appear smaller than a diamond of the exact same carat weight. Overall, the most important thing to consider when choosing a sapphire is the color. There is no standardized color-grading system for colored gemstones but considering the following will help guide your choice:

Hue: the stone’s balance of color as it relates to neighboring colors on the color wheel. Variations include blue, slight green, strong green, slight purple and strong purple. The closer to “true blue”, the more valuable the sapphire will be.

Tone: how light or dark the color is ranging from very light to very dark. Anywhere in the medium to dark range is ideal.

Saturation: how vibrant the color is ranging from dull/weak to pure vivid. The closer to pure vivid, the better.

Just like diamonds engagement rings, sapphire engagement rings can come in a range of different styles that can be customized to meet your preferences. From vintage-inspired to sleek and modern, the sky is the limit. Here are a few popular sapphire engagement ring styles: