How do you get a petrify orb?

I belive you can get it in Mt. Cornet. It's in a cave on the path to Spear Pillar. You'll need Surf and Watergfall I believe.

Once you first exit Mt. Coronet and arrive in a snowy area (like you were going to go to spear pillar), go left (the only way to go at this point :) ) and go north (not up the steps) when the path...

In Diamond and Pearl, after you catch Diagla/Palkia, there is a shiny object behind them. go collect it. for Diagla, its the adamant orb. for Palkia, its the lustrous orb

Let Palkia hold the lustrous orb, and let Dialga hold the adament orb. It boosts their special moves' damage.

Nothing. They just float around.