I just started to read x-men titles and am curious about Mystique's limits. If mystique shape shifts into Wolverine, does she have adamantium bones? In the same way if she shifts into someone like Colossus is she the same hardness or would she only appear that way?

Seeing as nobody's answered I might as well post. No she doesn't gain adamantium bones and no she wouldn't be able to mimic Colossus' durability. She might be able to get close though-she can create body armour presumably made from her own bone, and even make it look (and behave?) like metal. Whether she can actually create metal is a grey area, either it actually is metal or a metal analogue of some kind.