Any question answered...

It appears to be a really weird stem, they have applied some kind of chromoplastic coating over the aluminium. They could've just mirror polished the metal and anodised it making it last pretty much forever. I have never seen any metal component that had this finish very strange. But it a purely cosmetic issue.

Thanks, yeah it seems so strange to me, I've never seen any kind of metal look like this one does - with the silvery bit flaked off, it's a dull, opaque cream/grey. The silvery bit that's flaking off is like gold foil. It's made by Kalloy and was cheap, so that might explain it.