If you put energy into anything really with the idea that it may cause some change, your pattern recognition system will rev up looking for signs of those changes, so it could just be the lack of perfect reference frame in memory leading the mind to see the crystal as clearer. The other reason is, if you hold it a lot, the oils from your hands may seep into the tiny cracks in the crystal. In any case I wonder what the Cs would say about it.
Those are interesting thoughts and I admit that oils from the hands never even occurred to me.
The particular crystal I was referring to, does have a significant crack along the bottom
where it was broken from the original matrix, so it is possible that oils could get in there.
What's interesting though is that the crack is at the bottom and the crystal actually began clearing from the top, downward. It's not a small crystal, it's about 6 inch's high and over 8 inch's in circumference and I'm just not sure that there would be enough oils to have much of an effect on a crystal that size.
And it would seem that crystal dealers might have noticed that oils unclouded them and would already be greasing them up in the back room to sell as clear crystals, for a higher price.
And I only assumed of course, that it was body heat that might be doing it, so then again, if small amounts of heat could clear them, crystal dealers would have them in heated cases, clearing them to sell as more "pure".
So other causes aside, that leaves expecting something to happen because of energy being put into it, and that seems probable too, though I can think of a lot of energy and expectation put into things that never produced any results at all.