Flint

piikivi is a mineral obtained from gravel.

Mining
When a block of gravel is mined, there is a 10% chance for a single piece of piikivi to drop instead of the gravel block. When mined with a Fortune-enchanted tool, this chance increases to 14% at Fortune I, 25% at Fortune II, and 100% at Fortune III. Gravel mined using a tool with Silk Touch or gravel fallen on a non-solid block never produces flint.

Trading
Novice-level Fletcher villagers have a 50% or $2/3$ chance to offer 10 pieces of flint for 10 blocks of gravel and an emerald.

Unlike other villager trades, trading flint is not renewable due to the trade consuming non-renewable gravel.

Trading
Apprentice-level fletcher villagers buy 26 flint for an emerald.

Apprentice-level leatherworker villagers have a $2/3$ chance to buy 26 flint for an emerald $$, and always offer the trade $$.

Journeyman-level toolsmith villagers have a 40% chance to buy 30 flint for an emerald in Java Edition, and always offer the trade in Bedrock Edition.

Journeyman-level weaponsmith villagers buy 24 flint for an emerald.