I just received a shipment of Scharffen Berger 3oz. semi-sweet bars. I
opened the first one and found a powdery mist covering the chocolate.
It's barely noticeable at this point, but a finger swipe over the
surface leaves a clear trail.

It could be the natural oxidation of fine chocolate, but as a novice,
it alarms me because having read many of the posts here, it could also
be indicative of product about to spoil. I still have 11 more bars to
consume, so should I return them now, or am I fretting over nothing?
It doesn't taste spoiled (yet).

Also, should the product itself be so HARD? I mean it behaves like a
plane of glass and doesn't melt in your mouth very easily. Are these
typical characteristics of 62% cacao, or did I get stuck with stale
chocolate?

I paid $47 for these things, so I really need to know!

-- Thank You