Does stoneskin work if a druid wildshapes into air elemental form?

@nigbose @ChrisPerkinsDnD @JeremyECrawfordDoes stoneskin work if a druid wildshapes into air elemental form? yes, still applies, though maybe hard to picture. stone shards whipping around inside it?

— Mike Mearls (@mikemearls) March 21, 2016