I've been playing this game for days now and the crystal just won't appear! I've been playing around abit with the clock on my comp to speed things up at times, so would this mean the crystal doesn't appear?!!!

If you've been altering your computer's system clock, it will affect that puzzle. It should show up eventually, but the game's real-time engine relies on an accurate system clock and you have changed yours. Try setting the clock to the correct time and leaving it there. Then be patient and wait for the game to recover from the time travel.

Thanks! Sorry i should have marked it as a spoiler, but don't know how. It's finally come now.