Sapphire is a precious gemstone, typically blue but found in a range of colors, except red (as red sapphires are classified as rubies). It is a variety of the mineral corundum, composed mainly of aluminum oxide with trace elements such as iron, titanium, or chromium that give it its color. The deep blue hue, often associated with sapphires, is due to the presence of iron and titanium. However, sapphires can also come in yellow, pink, green, and even colorless forms.

Sapphires are known for their hardness, ranking 9 on the Mohs scale, making them one of the hardest gemstones after diamonds. They are used in various jewelry pieces, including rings, necklaces, and earrings, and are considered symbols of wisdom, loyalty, and nobility. Sapphire is also the birthstone for September. The stone is typically transparent but can sometimes have a star-like effect, known as asterism, caused by rutile inclusions.