Each stone varies. Astrophyllite has been found in Greenland, Norway and the USA however the majority of the material on the market has come from the Kola Peninsula of Russia. This stone is good for self-knowledge, realization of multidimensional self, self-acceptance, forgiveness and infusion of oneself with Light. 
It also helps one accept one's shadow self and reclaim their power. It can energetically protect against radiation and electromagnetic fields. The nervous system and brain functions are regulated and enhanced and it's useful in detoxification on an energetic or physical level.