Chlorophyte Bar

Chlorophyte Bars are crafted from 6 Chlorophyte Ore, an end-game Hardmode ore which can be found in the Underground Jungle, or grown in mud.

Crafting all Chlorophyte equipment, excluding the arrows, bullets, Spectre equipment and Shroomite Bars, requires 288 Chlorophyte Bars, or a total of 1,728 Chlorophyte Ore.

To craft one set of each (including helmet/body variants) Chlorophyte armor, Spectre armor, Turtle armor, Beetle armor and Shroomite armor, you'd need a total of 354 Chlorophyte Bars plus the various other materials, which equals 2,124 Chlorophyte Ore.

Trivia
Chlorophyte is a reference to chlorophyll in chloroplasts in plant cells.