A 1 Extended

In order for any of the crytals to undo hidden-ness by means other than removing concealment (as the lesser and greater crytals can in certain cases), one would have to accept the notion that a creature treating you "as if you were invisible" as a result of succeeding on a hide-check is an "invisibility effect" (as specified in the item description).

Ignoring the issue whether skills create "effects", the main issue with this is that being hidden and being simply invisible are different; with the most obvious distinction being that someone attacked by an invisible attacker is denied their dexterity (Rules Compendium p. 77), while someone attacked by a hidden attacker is not only denied their dexterity but also flat-footed (Rules Compedium p. 92). Being 'hidden' is thus more than a simple invisiblity effect, so negating just the pseudo-invisiblity portion of hiding would not undo hidden-ness in its entirety, resulting in a irreconcilable rules-discrepancy. Thusly, this is a non-sensical (albeit creative) notion. I hope this helps clear things up.

Q 2 Reposted from last thread

I have a simple question with many ramification that keeps on popping up for me, as the books are largely silent while Dragon Mag, the WotC website and the FAQ's are often inconsistent/unclear on the matter:

What is "Force"?

Different views welcome.

Addition: as an example of an inconsistency, the Meta-breath spell Animate Breath from Draconomicon (Spell-compedium version superceeding should not affect the original's wider rule-implications) calls Force out as an energy type (both specifically and in context), but the glossary does not list Force as an energy type.