The "495" Hallmark on a piece of gold means that it is 49.5 percent gold and 50.5 percent other metals. This is known as a standard mark, and it shows the purity of the metal as well as its shape.
On any given piece of gold, there are four standard marks: AB sponsor or maker, standard mark, assay office mark and the date. Since 1998, the date mark has been optional, but the other three still remain compulsory.
In addition to the standard mark, the sponsor mark shows the company responsible for sending the article to the assay office, and it can be a manufacturer, retailer or importer. The assay mark shows where the gold was tested. The date mark shows the year the metal was tested.