In Agents of SHIELD S02E10, What They Become, we see
Raina, Skye, and Tripp enter the Temple and are exposed to the contents of the Obelisk, a crystal which blasted out a shockwave of air.
Afterwards, 2 of them are affected, but not Tripp. Why wasn't he affected, why were
Raina and Skye coated in stone?
What happened in this scene? Is this explained by something in the Marvel Comics?