Diamond: £45,000 per gram
The most expensive diamond ever sold was the Pink Star, a South African gem that fetched £51.7m in 2013, working out to £4.38m per gram. At 59 carats, the nearly-12g oval diamond measures 2.69cm by 2.06cm.
However, a less rare, colourless 1-carat diamond goes for around £9,000 per carat, which equates to £45,000 per gram.
#4 & #7... Not sure what I am missing here.. But it seems that if I grind my solid gold bars up into a fine powder I can increase it's value by 700%.. from $28 to $200 a gram??