I started a new world recently, getting bored of having everything, and have worked up to Necro Armor, passed the Underground Jungle and Dungeon, and am still doing the Underworld. However, I have an issue; life crystals. I have searched everywhere (I even took an exploratory trip into the Underworld) including the Underground Jungle, Underground Layer, Cavern Layer, Dungeon, and Underworld. I have only found four life crystals thus far and I am getting frustrated at dying constantly due to my lack of vitality to resist enemy attacks. What is the problem here? Where should I search for life crystals? Am I missing something?