This mysterious element seems to be present in small quantities in ancient fossils. Maybe you can combine these shards into a piece large enough to have a measurable effect on something!
Extractium Shard price in Growtopia: sells for about 5 WL, buyers pay about 3 WL (median of 212 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: QUFOSSIL, SAGUER, VENDDL, OYBG, QCTR