Sapphire

By default, blue is associated with sapphires, and the most sought-after shade is a clear cornflower blue. However, the gem can come in all colors (with the exception of ruby red) and even be colorless for white sapphires.

Like all gemstones, sapphires have inclusions of different types: minerals, channels, or liquid inclusions.

However, far from being imperfections that would devalue the stone, as is the case for diamonds, these inclusions guarantee its authenticity and natural origin, since synthetic sapphires do not have them. The nature of the inclusions also makes it possible to determine the type of deposit from which the sapphire was extracted.

Naturally, inclusions that are too large or too numerous affect the color and appearance of the sapphire, which generally depreciates the value of the gem, with the exception of rutile inclusions, which enhance it. Indeed, rutile needle inclusions give sapphires, like rubies, soft reflections called "silks." Depending on their orientation within the stone, these inclusions produce either chatoyancy, which is a luminous phenomenon reminiscent of the slit pupil of a cat's eye (the sapphire is then called a "cat's eye"), or an asterism effect, which is a luminous phenomenon that forms a star or a cross on the surface of the stone (the sapphire is then called a "star sapphire").