Sapphire is a precious gemstone that is most commonly known for its striking blue color, although it can come in a variety of other colors such as pink, yellow, green, and even colorless. It is a variety of the mineral corundum, which is composed primarily of aluminum oxide. Sapphires are typically very hard, ranking 9 on the Mohs scale of hardness, making them one of the hardest natural materials on Earth.

The blue color in sapphires comes from trace amounts of iron and titanium within the crystal structure. Sapphires are often used in jewelry, particularly in engagement rings, and are considered one of the "Big Three" gemstones, alongside diamonds and rubies. They are also highly prized for their durability and vibrant colors.

Sapphires are mined in various parts of the world, including Sri Lanka, Myanmar, Thailand, and Australia. Some of the most famous sapphires include the "Star of India" and the "Blue Hope Diamond" (though technically a blue diamond, it shares a similar color). The gemstone has long been associated with nobility, wisdom, and loyalty.

In addition to their use in jewelry, sapphires are sometimes used in industrial applications, like watch crystals and optical components, due to their durability and scratch resistance