A VenomGem is quite a valuable item in the game. It can be found in the bottom 8 layers of the map, and it has a 1/200 chance of one being in every chunk.
VenomGems are obtained by mining VenomGem Ore. When holding a VenomGem in your hand, every ten seconds there is a 45% chance that you will receive VenomGem poison and a 20% chance if it is in your inventory. When mined, it creates a purple particle effect similar to that of an Enderman's. They glow as if enchanted and need an Emerald Pickaxe to mine. The Player can receive several VenomGems and VenomBlades after defeating Herobrine for the third time.
With a crafting table, a VenomGem can be made into a VenomBlade with the same recipe as any other sword (two VenomGems and a stick) but cannot be made into any other tool.