Lots of different sugar types exist, and the most common types are:
Granulated sugar or white sugar is made from sugar canes or sugar beets, that is highly refined sugar. Granulated sugar is also available in cubes or tablets of various sizes, as well as a variety of textures.
Superfine sugar (aka. castor or caster sugar) is more finely granulated, and dissolves almost instantly.
Confectioners' or powdered sugar is granulated sugar that has been crushed into a fine powder with a small amount of cornstarch is added to prevent clumping.
Decorating or coarse sugar has granules about four times larger than those of regular granulated sugar.
Brown sugar is white sugar combined with molasses, which gives it a soft texture. The two most common types of brown sugar are light and dark. The lighter the brown sugar is, the more delicate the flavor.
In the bar sugar is usually used to sweeten drinks and to rim glasses.