One could turn any asset into a currency with a blockchain.

The big question behind a cyrpto-currency based on gold is: Is the gold real?

Both monetary history is full of stories of people selling gold plated bars of lead and banks over leveraging their gold assets.

A blockchain that follows the production and distribution of gold would be extremely valuable for people in the gold industry.

But I would be wary of such coins as a long term investment.

I would rather have a gold coin in a safe than an alt-coin that says it is backed by a gold coin that is out there in the aether somewhere.