Platinum is a metal, not a stone. Need more info in the question. You can go to any jewelry store and have them look at your ring and tell you what it actually is since platinum is not a stone.
You don't get the magna stone from buck in Pokemon platinum.
To find a shiny stone in platinum you have to dig in the underground tunnel.
It does not evolve with a dusk stone in Pokemon Platinum
there is no bronze stone
In the Underground.
Just confirmed April 30
Go underground and you could get a water stone there
on route 225 there will be a dawn stone
Not in the US yet, sorry. There hasn't been any confirmed dates of the update that will allow for Platinum.
It has been confirmed that it is coming out in March 22,2009
Yes, but dates are not confirmed as of yet.
happini can evolve with a oval stone