These crystals grow naturally in caves. They don't actually glow - bioluminescent organisms feed on them and emit light. Also heat - be careful!
Aqua Cave Crystal price in Growtopia: sells for about 20 WL, buyers pay about 20 WL (median of 137 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: AUKUU, JOZVEND, LTLXT, XHYLIST, KENDAS