In Australia carat is no longer a standard to stamp gold. We have
to stamp parts per thousand. Is this just us (Australia) or do other
countries subscribe to this?
It’s the same in the UK too. Sterling is 925, fine silver is 999,
18K gold is 750, 9K gold is 375, platinum is 950 (or sometimes 900 I
think), as is palladium. The assay offices require by law that
anything made of precious metal which is above certain weight limits
(7.78g for silver, 1.0g for gold and 0.5g for platinum), if it is to
be described as that particular precious metal, it must be sent for
assay and hallmarking by an assay office (of which there are four in
the UK). If a piece falls within that category, but it’s not
hallmarked by an assay office, it can only be described as “white
metal” or “yellow metal” for example.