Sapphires have a vitreous luster, meaning they have a glassy, shiny appearance. However, the actual texture of a sapphire is smooth and hard.

Here's a more detailed explanation:

* Hardness: Sapphires are known for their hardness, ranking 9 on the Mohs Hardness Scale. This means they are very resistant to scratching and abrasion, resulting in a smooth surface.

* Surface: The surface of a polished sapphire is smooth and reflective, due to the hardness and the way it's cut and polished.

* Internal texture: Sapphires can have internal inclusions, which are tiny imperfections within the crystal structure. These inclusions can sometimes give the sapphire a slightly cloudy or milky appearance, but they don't affect the overall smoothness of the surface.

So, while the luster is glassy, the actual texture is smooth and hard.