Flint and Steel

The flint and steel is a tool used to light fires.

Natural generation
Chests in Nether fortresses may contain flint and steel.

Usage
When on top of a solid, fully opaque block or on the sides of a flammable block, the flint and steel sets a fire on the surface on which it was used. Flint and steel has 65 uses. If used on a transparent block (such as glass) or a block which is underwater, it will not start a fire but still will consume durability.

It also can be used to light Nether portals.

In both survival and creative, using flint and steel on TNT will set it off. Flint and steel can also be used to detonate creepers.

Enchantments
Flint and steel can receive the Unbreaking enchantment, but only through the use of an anvil.

Trivia

 * In Adventure mode, flint and steel cannot light fires, nor can it ignite Nether portals. However, it can still ignite TNT and Creepers.