Nitre is a Mineral resource obtained by mining smooth Boulders, which will drop at least one (along with other minerals) upon being mined. It also occasionally falls during undergroundEarthquakes. It can be used to craft Salt Licks and Gunpowder.
Nitre was changed to be dropped by the small, smooth boulder in The End of the Beginning update.
Nitre, a.k.a. Saltpeter (Potassium Nitrate, KNO₃), is a common ingredient in creating gunpowder in the real world. It is also an ingredient in fertilizer. Although it cannot be directly used as fertilizer in game, it can be used to craft Compost Wrap, which can be used as fertilizer in Don't Starve Together.
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