:o Wow. Thanks for the tips.

Another interesting thing I noticed about chlorophyte is that it's most likely triggered by the presence of jungle grass, rather than an actual jungle biome, since I accidentally clentaminated parts of mushroom biomes when clensing my main world, turning them into pieces of underground jungle in the process. Those small pieces (some no larger than maybe a dozen grass-covered mud blocks in the middle of a mushroom biome) then produced anything from chlorophyte to life fruit to Plantera's Bulbs. And they also sometimes spawn underground jungle enemies as well.

It can be constructed anywhere in the stone layer (above the underworld, this one is about 2/3 down a hellevator shaft), although it only produces chlorophyte in hardmode. Creating 5x5 blocks of mud with a piece of chlorophyte in the middle is probably the most efficient way of farming, although there can't bee too many of them close together, since chlorophyte stops growing once a certain concentration has been reached. The above farm originally had more growth cells, with nothing being produced. Only when I removed some of them, did chlorophyte finally start growing (technically, it replaces mud around it), although the growth still stops once around 35-40 pieces of ore are grown.

Question.. does it work only underground? Also, I thought it worked only in the jungle, or does it grow anywhere there is mud?

Oh my God, I never knew Chlorophyte worked like that. Thank you! I always just assumed it just randomly spawned, since it.. well, seemed to just randomly spawn. I'll set up a farm later.