07/24/2026
Ruby and sapphire are both the mineral corundum. What makes them different is their trace elements: chromium impurities create red rubies, while iron and titanium create blue and other colored sapphires. If a corundum is red, it's classified as a ruby. Any other color is a sapphire.Both gemstones are made of aluminum oxide (Al₂O₃), have the exact same crystal structure, and share a durability of 9 on the Mohs scale. Because they share the same foundational chemistry, the differences come down to specific color mechanics and gemstone rarity.