Fire

Fire is an important tool in the game. It is essential for cooking food and refining sand and ores. Fire can no longer burn down buildings or ships in the current version of the game.

Firemaking Tools
These tools are used to set any flammable object on fire. Click on the item you'd like to burn to ignite the fire. Lower tier tools take longer to start a fire.

Flint
A basic tool crafted with two cut stones, this takes quite a while to start a fire.

Flint and Steel
Crafted from one cut stone and one steel, it used to be the best fire-making tool in the game for non-admins. Its description states that it has a 65% chance to light a fire, though in practice it lights a fire every time and takes less time than flint.

Bluesteel Igniter
The best non-admin firestarter in the game. Added in the Bluesteel update, this tool has a 75% chance of lighting a fire. Although it is better than Flint and Steel it is not recommended to make due to the large cost, and the fact that two Flint and Steel can give the same result. Its appearance is similar to a ladle colored blue.

Zippo Lighter
This is an admin only firestarter. Not much is known about except for the fact that it can 100% make a flammable object on fire. It is made with a Left Arm, and non-admins can only acquire this tool through the help of an editor or an admin/mod of the game. During the Christmas update, Holiday Trees can give these in gifts.

Cooking
Uncooked fish and meat will lower your health, so it is important to cook them over a fire. Baked goods like bread and pie need to be cooked in order to be eaten. Other foods, like fruits, vegetables, and juices, cannot be cooked. Food does not burn if left on the fire for a long time.

At first, the easiest way to cook is with a large leaf pile: Crafted by combining three leaves in handcraft, this object will burn much longer than the individual leaves and lets one easily cook multiple foods at a time.

The firepit structure burns forever once ignited so you don't have to worry about finding more fuel.

Later in the game, you can make a stove, which also burns forever once ignited and has a larger, flatter cooking surface than the firepit.

Refining
Ores can only be refined on a firepit (copper and iron only), or in the glowing part of a forge (up to steel) or smeltery (all ores). Refined ores, like refined iron, steel, and gold, are essential for many tool and building recipes.

Glass
Sand, found on the shore on every island, can be made into sandstone or glass. Glass is quite useful; you can make lanterns, windows, and more with it. Sand can be turned into glass by putting it on any fire or forge.

Explosives
Gunpowder blows up when put in or near fire. The problem is, you're usually killed in it. To prevent this, instead of lighting it, you place a burning leaves next to it, giving you enough time to run away.