Well, it was only a matter of time before current world economics caught up with Sonic the Hedgehog, and it looks like he's now trading emeralds and rings for literal pieces of solid gold.
To celebrate Sonic's upcoming 35th Anniversary, the Sonic and SEGA team have teamed up with a number of high-end jewleery and gold retailers across Europe, Canada and the USA to release small bars of 999.9 fine gold, weighing 0.5G minted by Switzerland-based gold experts PAMP.
Spotted by the folks over at Sonic Stadium it's being sold for around £85/$110 and features a limited batch of just 5,000 being made. Sonic himself features on the golden bar alongside a Chaos Emerald on the back to make this somewhat of a collectable.

Not that I am a gold expert, far from it, but seeing gold's not so volatile price over the years and a slow increase in return on investment, it could be a solid purchase for those wanting to mix nostalgia with a phyiscal investment in a collectable that will likely hold value (this is not investment advice).
However, I do feel like it's off-brand for Sonic and SEGA. I understand they are very relaxed with who buys their license and what happens with their franchises, but this one doesn't relate to the Sonics' gaming history. It feels like a quick cash grab for the brand, slapping an iconic character on a bar of gold. But that's just my opinion.
These are available to buy from retailers such as BGASC, CDNCoin and Metal Market, should it interest you. Each one comes with a certificate of authenticity.