Maryland Criminal Law Section 5-618
§ 5-618.
  (a)   Except as authorized in this title, a person may not possess or purchase a noncontrolled substance that the person reasonably believes is a controlled dangerous substance.
  (b)   To determine if a person has violated this section, the court shall include in its consideration:
    (1)   whether the noncontrolled substance was packaged in a manner normally used to illegally distribute a controlled dangerous substance;
    (2)   if the noncontrolled substance was purchased, whether the amount of the consideration was substantially greater than the reasonable value of the noncontrolled substance; and
    (3)   whether the physical appearance of the noncontrolled substance is substantially identical to that of a controlled dangerous substance.
  (c)   It is not a defense to a prosecution under this section that the substance a person possessed or purchased was not a controlled dangerous substance if the person reasonably believed that it was a controlled dangerous substance.
  (d)   A person who violates this section is guilty of a misdemeanor and on conviction is subject to imprisonment not exceeding 1 year or a fine not exceeding $500 or both.