what they are talking about are your pure stamina gems.
I don't play a pally tank, but I think you should go for hybrid gems that include 2 helpful stats. This way you build Dodge/parry/Mastery at the same time you are gaining some stamina. The new Cata model has us with large health pools just with our gear and allows us to work on other stats such as aviodance and mastery.
Go for pure mastery (Chimera's eyes in your case) gems in yellow and Prismatic sockets, and green gems in blue sockets. I think thats more of what you are looking for.
When doing this work towards keeping your dodge and parry close together becasue of diminishing returns. I would also not gem for expertise, just another observation.