Perhaps you should actually read the History and setting of the PlaneShift world first.
The whole of Yliakum is reliant on a massive crystal embedded in it\'s roof, which absorbs sunlight from the surface of the planet and radiates this light down onto our world, enabling a day and night cycle in a place which would otherwise be suffocated in darkness.
Talad, Yliakum\'s God, is the lord over all Glyphs and crystals. It stands to reason that he would allow these gems to grow all over his world as decor or to give his inhabitants a preliminary monetary currency (remember that soon we\'ll have Trias, not crystals).
Crystals are also the staple source of nutrients for the Kran, Talad\'s own tailored race. In order to survive, Kran need to \'eat\' the crystals; some have different tastes, thus why we have Rubies, Emeralds and Diamonds.
