A Guide to Colored Gemstones

A colored center stone turns a ring into a signature. But gemstones vary widely in durability and how they’re judged — here’s what to know before you choose.

The big three

Sapphire comes in every color but red (most famously royal and cornflower blue). At 9 on the Mohs hardness scale, it’s second only to diamond and ideal for everyday rings. Ruby is the red variety of the same mineral (corundum) — equally durable, with a glowing red that pairs beautifully with yellow gold. Emerald offers an unmatched green, but it’s softer and more included; a protective setting (like a bezel or halo) keeps it safe.

How gemstones are judged

Unlike diamonds, colored stones are valued mostly on color — hue, tone, and saturation. The goal is a vivid, evenly-distributed color that stays bright. Clarity matters less; many gemstones are expected to have some inclusions. Cut is judged on how well it shows the color.

Durability at a glance

• Daily-wear ready: Sapphire, ruby (9 Mohs), and moissanite (9.25).
• Wear with care: Emerald, aquamarine, morganite (7.5–8) — great in protective settings or for earrings and pendants.
• Occasion pieces: Softer stones like opal — beautiful, best for necklaces and earrings.

Birthstones make it personal

A birthstone stud or pendant is a thoughtful gift — in stock and ready to ship in 3–7 business days. Explore gemstone studs, or for a center stone that makes a statement, see our colored-stone engagement rings.