Why don't you use one of the Pioneers crystal tears?
Here is a description:
The crystal tears was created by a pioneer (duh) that had troubles in his pilgrimage. What troubles? The lands he crossed had different gods ruling them, all of them somehow eager to stop him. After suffering so many losses after the gods, his family and everything he loved was destroyed just so that he would stop the pilgrimage. Filled with sorrow he continued his quest and whenever he wasn't seen, he shed a tear. Only one tear at each of the most secret of places. When he died the tears crystallised and the gods fear it, as a single touch from it and then dies.