Plant it to grow Glass Block. People inside this should not throw stones.
Glass Block Seed price in Growtopia: sells for about 60/WL, buyers pay about 100/WL (median of 13 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: FN50, LUMSI, EEPSON, TGNSELL, HOWPY