I googled for iran oil gold, found this:
https://www.cnbc.com/2018/05/16/iran-oil-trumps-sanctions-create-crude-trading-boom-in-china.html
... but they used trading volume as judgement basis.
My experience is that the use of trading volume to make claims, is quite often a misrepresentation.
It's a typical Silver Doctors trick, they compare trading volume with annual production, as in "an entire annual US silver production was traded in a single day".
That, is purely scam. It completely ignores that a single quantity underlying of the derivative, can be traded more than 1 time on a day. A single silver futures contract of 5000 oz, can be traded ten, hundred and thousand times on a single day, yet the required amount silver (if needed anyway, since futures nearly always end in delivery of dollars not in delivery of the underlying product) is just that 5000 oz.
With 5000 oz, one can generate a daily trading volume of halve the entire annual world production, by trading it 100000 times on the day.
"High frequency trading" can generate millions trades on a single day.
So one has to be wary to accept claims based on volume.
What’s the deference with physical silver?
Physical metal can be traded thousand times a day, like paper silver. Doesn’t mean there is thosand muliples of the same silver.

