http://law.ato.gov.au/atolaw/view.htm?docid=GST/GSTR200310/NAT/ATO/00001 said:
Bears an accepted mark or characteristic
23. To be tradeable on the international bullion market, the metal must bear some mark or characteristic on its face accepted by the market as identifying and guaranteeing its fineness and quality. An example of a mark is a hallmark used on bars. An example of a characteristic is the characteristic pattern or design and noted weight and fineness found on a bullion coin that identifies the coin as issued, backed and guaranteed as to fineness by a government.
24. For example, granules do not bear any mark as to their fineness and quality and are therefore not in an investment form. On the other hand, gold bars bearing an internationally accepted hallmark, including hallmarks listed in the Industry Catalogue of Gold Bars Worldwide (ICGB), do bear such a mark and are therefore instantly accepted on the international bullion market as to their guaranteed fineness and quality.