https://ffxiv.gamerescape.com/wiki/Effervescent_Water

It makes a few items. I'm assuming its more then usual cause of twin thread which is lvl 68. But I'm on midgard as well, and I've noticed lately alot of the somewhat older mats, specially between 50-60 cost more then before. I'm guessing cause as people moved on from 60-70, less gathering of older mats and people being lazy to get their own mats... So demand is higher, which raises prices.