Ruby vs Sapphire
Here is a fact that surprises many people: ruby and sapphire are the same mineral. Both are varieties of corundum (aluminum oxide). The only difference is color—red corundum is called ruby, while all other colors (blue, pink, yellow, green, orange, purple) are called sapphire. Despite being the same mineral, they have very different markets, histories, and values.
| Factor | Ruby | Sapphire |
|---|
| Mineral | Corundum (red) | Corundum (all other colors) |
| Mohs Hardness | 9 | 9 |
| Most Valued Color | Pigeon blood red | Cornflower blue (Kashmir) |
| Color Agent | Chromium | Iron & titanium (blue); varies by color |
| Price (Fine Quality) | Highest per carat of any colored gem | Very high; generally less than equivalent ruby |
| Rarity | Extremely rare in fine quality | Rare in fine quality; more sources available |
| Birthstone | July | September |
| Famous Examples | Sunrise Ruby ($30.3M), Liberty Bell Ruby | Star of India, Princess Diana ring |
The Ruby-Sapphire Boundary
Because ruby and sapphire are the same mineral, there is an ongoing debate about where ruby ends and pink sapphire begins. There is no universally agreed-upon dividing line. Generally, a stone must display a dominantly red hue to be classified as ruby. If the pink is too strong relative to the red, the stone is classified as a pink sapphire, which is significantly less expensive.
Value Comparison
Top-quality rubies consistently command the highest per-carat prices of any colored gemstone—fine Burmese pigeon blood rubies have sold for over $1 million per carat at auction. Fine blue sapphires are also very valuable but generally cost less than rubies of comparable quality. Pink sapphires, padparadscha sapphires, and other fancy colors have their own value scales.
Which Should You Choose?
Since both stones have identical durability (9 Mohs), the choice comes down to color preference and budget. Choose ruby for the passion and prestige of the king of gemstones. Choose sapphire for the widest range of color options and a broader selection at more varied price points.
Browse our ruby jewelry, blue sapphire jewelry, and pink sapphire jewelry.