Iowa Code § 453B.4: Measurements.

For purposes of measurements under this chapter, the weight of a taxable substance shall be measured by its weight in metric grams in the dealer’s possession. If a taxable substance consists of a mixture containing both marijuana and another substance or combination of substances listed in the definition of taxable substance in section 453B.1, the taxable substance shall be taxed under section 453B.7, subsection 2.