The falling crystals are commonly called 'Tomb Crystals', due to some explorers claiming to have found strange corpses inside of them.
Broken Tomb Crystal releases poisonous vapors and mutagenic dust. While acute poisoning is most common in Gem Robbers (Those who make a living chasing down crashed Tomb Crystals and looting them) and others who risk direct exposure, Tomb Crystal pollution contaminates air and water across the whole Bloodlands. Most of the people who live here—especially the poor farmers and swineherds—will eventually die from it.
Even then, the dead are not safe from Tomb Crystal poisoning. If a body is not buried with the proper magic rituals, it will rise as a Lith Zombie or LithWight.