28 C.F.R. § 76.2
(h) The term Personal Use Amount means possession of controlled substances in circumstances where there is no other evidence of an intent to distribute, or to facilitate the manufacturing, compounding, processing, delivering, importing or exporting of any controlled substance. Evidence of personal use amounts shall not include sweepings or other evidence of possession of amounts of a controlled substance for other than personal use. The following criteria shall be used to determine whether an amount of controlled substance in a particular case is in fact a personal use amount. The absence of any of the factors listed in paragraphs (h)(1) through (h)(5) of this section and the existence of the factor in paragraph (h)(6) of this section shall be relevant, although not necessarily conclusive, to establish that the possession was for personal use, and amounts in excess of those listed in paragraph (h)(6) of this section may be determined to be personal use amounts where circumstances indicate possession of the substance without an intent to distribute or to facilitate the manufacturing, compounding, processing, delivering, importing or exporting of the controlled substance.
(ii) One gram of a mixture or substance containing a detectable amount of—