Emeralds are May's birthstone. This particular one is lab-created, which you'd think is less classy, but they're much prettier.
Emerald Necklace price in Growtopia: sells for about 1 DL 50 WL (median of 5 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: ZEZF, BUYLIFEGOAL, NANSX, VANVENDO, CH80