From observing the transit times through Earth of waves generated by earthquakes
The epicenter of an earthquake is the location directly above the hypocenter on the surface of the earth. The “Ring of Fire” also called the Circum-Pacific belt, is the zone of earthquakes surrounding the Pacific Ocean — about 90% of the world's earthquakes occur there.
Reincarnation. upon returning to the earth again, they shall be reincarnated into a specific lifeform based on how well they lived their prior life.
The ones that have a higher hardness than the glass. The glass hardness is 5.5 so only the quartz will scratch it with a hardness of 7.