TNT is not very useful in combat. Detonating it would kill both you and the enemy. It can be used as a mining method, detonating deep into a mine.
TNT may currently be obtained only from the Ghost Miner.
When interacted with, there will be a button that will the player to detonate the TNT. It can may detonated in the inventory to obtain various kinds of rare loot, such as rare Geodes or ores such as Promethium Ore, Titanium Ore and etc.
Detonating the TNT will also yield the player 10 000 Mining XP.