Flint and Steel

Flint and steel is a tool used to place fire.

Pocket Edition
Used to detonate TNT.

Trading
Flint and steel can also be obtained by trading from villager farmers, but not as of snapshot, villagers will no longer sell flint and steel.

Use
When used with right-click on top of a solid, fully opaque block or on the sides of a flammable block, flint and steel places fire in the air block directly adjacent to the surface on which it is used. In both Survival and Creative using (right-clicking) flint and steel on TNT will set it off. Flint and steel has limited uses, only 65. When right-clicked to place fire, a point of durability is drained whether or not the surface it is used on is correct for the placement of fire. However, as it is not a block-breaking tool, it can be used without damage to break blocks using left-click.

The fire-starting ability of Flint and Steel makes it a versatile tool and weapon. Despite the reduction of its spread, fire can still be useful for some clearing jobs. It will quickly remove fences or wooden stairs (in a roof for example), clear wooden or cloth floors for renovation or thin out overly dense areas of forest. In most cases the fire will not cleanly remove all unwanted blocks, so final clearing with another tool is necessary. It has the advantage of working on its own while the player can do something else productive.

As a weapon, fire can be started beneath a mob or in a mob's path as a damage-over-time attack. For some pursuing mobs, this provides a "ranged" attack that does not expend arrows nor has the inherent danger of attacking in melee. The underlying block need not be flammable as the fire will still last for some time. Against Spiders or Endermen, the flint and steel can be used to cause damage without the mob becoming hostile. Whilst afield, it can be used to convert any nearby animal into suitable rations without the need for fuel or furnace. Flint and steel can also be used to set off the detonation sequence on Creepers.

Flint and steel has good synergy with netherrack and as such is the predominant lighting tool while in the Nether. This use can be extended back to the overworld by carrying netherrack, which provides brighter light and damage potential compared to torches. One can easily make a fireplace using flint and steel with netherrack and other non-burnable blocks to avoid the spread of fire. Additionally fire can be used to quickly dispose of unwanted items by dropping them and lighting them on fire or by using netherrack to make an everlasting incinerator with fewer containment issues than lava. Flint and steel, along with fire itself, explosions and redstone are the only ways to activate TNT.

Flint and steel requires a single iron ingot to manufacture, implying some degree of resources already established and as such may not be available early in the game depending on the player's direction of play. Over the long term, flint and steel tends to be a very minor expenditure of iron or flint compared to those resources' other applications.

Flint and steel can be enchanted, but only by using an enchanted book and an anvil. The only enchantment that Flint and Steel can get is Unbreaking I, II, or III.

Flint and Steel may be used to light or re-activate a Nether Portal.

Trivia

 * In Adventure mode, flint and steel cannot light fires, nor can it ignite Nether portals. However, it can still ignite TNT.
 * If you right-click with Flint and Steel on a transparent block such as glass, or a block which is underwater, it will not start a fire but still consume durability.
 * Despite being flint and steel, the recipe uses iron instead.
 * Flint and Steel is one of two items that were non-renewable in older versions, became renewable, and then became non-renewable again. The only other item that this has happened to is the Bottle o' Enchanting.