18 karat purplegold by Maarten van der Vegte

From Elements Series
This necklace is the result of the frequent questions I have been asked on
my purple gold and blue gold alloys. Every time I had to explain what
an alloy was and why we make alloys. So I thought it would be much
easier to explain this with an example.
The result is this necklace that contains 24 balls, which refers to the 24 karat gold.
18 balls are pure gold, and 6 are, in this case, made of aluminium.
Each ball weighs 1 gram, and because there are two kinds of metals,
there are also two volumes, because they each have a different specific gravity.
When mixed (alloyed), you’ll get a purple metal as the result.
In the middle of the necklace there is a 25th ball as the result:
the 18 karat purple gold. So what you’re wearing is an
18 karat purple gold necklace, it’s just not alloyed yet.