I don\'t think anyone\'s ever really thought about stuff like that, it was really just a complicated excuse for day and night underground, but here goes:
1. I don\'t understand what you mean. Why would it have to be in a desert?
2. It rains every five minutes for five minutes in ps, so the locals are probably used to bad weather (presumably yliakum is loosely based on medieval england, the only place I can think of where it rains that much).
3. I presume rain washes the dirt off it.
4. It\'s just the other side of the crystal.
5. Maybe. I\'m getting bored now.
6. Presumably the ps world is, like most other rpgs, based on earth.
7. Well, the crystal would have to be pretty big to light up such a large area, so the other side would be just as - no wait - bigger!
By the way, georgeD, I like the sig. Is that a pratchett quote?