Probably a really noobish question, but I thought that meant the card was unique. But that is noted by the little dot next to the card name.

So what does the diamond represent?

Sorry for the spelling error in the title. I typed it on my phone.

Can you specify a card? I'm not sure what you're referring to.

Same here, no idea what you're talking about.

Can you specify a card? I'm not sure what you're referring to.

Sea Source. In the top left corner, next to the cost to play, there's is a little outline of a diamond shape. Is that just part of the design? Looks like its on everything and I'm just over thinking it.

It's the credit symbol

That's not a Rez cost. Operations have Play costs. Only cards which get Rezzed (ICE, Assets, Upgrades) have Rez costs.