【How-to】What is difference between hb and bhn

For comparison, pure gold is 2.5, on the MOHs scale. That’s about the same hardness as your fingernail. That will not work for jewelry making. When white gold is prepared for jewelry making, by adding alloy metals, for example at 14kt or 58% pure gold, its hardness gets bumped up to 3.5 – 4.