 Brilliant Earth Group Inc.s stock BRLT, is slated to start trading Thursday, as the California-based jewelry companys downsized initial public offering priced overnight at 12 a share, well below the expected range of between 14 and 16 a share. The company raised 100 million as it sold 8.33 million shares in the IPO, half the previously expected offering of 16.67 million shares. 