Examine the surface finish, whether it is polished, honed, or flamed, for consistency across the batch. Pay close attention to the drilling precision where the cord exits the stone; it should be smooth to prevent wire fraying. For lamps with integrated LEDs, check the color rendering index (CRI >80) and heat dissipation efficiency. Requesting a pre-shipment sample is vital to verify that the natural stone pattern aligns with your brand's aesthetic expectations, as granite varies naturally in color and grain.