gram is usually used to measure light weight object
lightness is weight. luminance_unit is light_unit. weight_unit is unit_of_measurement. gram_molecule is metric_weight_unit. gram is metric_weight_unit. short_ton is unit_of_measure_for_weight. weight is measured_using_scale. gram_atom is metric_weight_unit. grain is unit_of_measure_for_weight. aluminum is light_weight.