"Strike it with a metallic weapon to generate a spark. This portable fire starter breaks after one use, but it can create a long-lasting flame if you use it near firewood."
— In-game description

The Flint is an item from The Legend of Zelda: Breath of the Wild. It can be found by Link under rocks, by breaking Ore Deposits or hitting and defeating some Talus or Pebblits. One spawns near a burnt out campfire in a cave in the Great Plateau while another spawns at Serenne Stable in the Hyrule Field region.

Link can use it once to start a Campfire or by striking it with a metal weapon while next to wood or burnt-out campfire though "Guardian" series and "Ancient" weapons can also generate sparks by hitting Flint despite being non-metallic and energy based. Link can also use it to light a unlit Cooking Pot. It is also required by Great Fairies to upgrade Link's armor specifically head accessories which includes the Amber Earrings, Diamond Circlet, Opal Earrings, Ruby Circlet, Sapphire Circlet, and Topaz Earrings.

Related Side Quests

During the side quest "Tools of the Trade", Isha asks Link to bring her 10 Flint for jewelry creation and Starlight Memories reopening. In the "The Spark of Romance", the honeymooner Jogo needs Flint to create a campfire to roast up some Baked Apples to keep his new wife Juney happy after she became unhappy with their honeymoon to Rito Village. He pays a Silver Rupee for a single piece of Flint. After quest is compete, Jogo will buy Flint from Link though he pays him based on the amount of Flint. As Flint is easily obtained, this makes selling Flint to Jogo a useful why of acquiring Rupees though he can sell Baked Apples to Juney in the same manner after "The Apple of My Eye" is completed which is even more lucrative as Apples are the most common material that can be easily made into Baked Apples though acquiring Flint is generally a faster process.