This website says mercury: Maybe that is Y some feel sick.

http://www.bright.net/~jimsjems/crystal.html

Hematite: Silver-gray metallic. (High iron, mercury) One of the most grounding of all stones. Mental clarity, concentration, memory, practicality, helps study, bookkeeping, detail work, sound sleep. Confidence, will power, boldness. Used to calm hysteria and anxiety. Best worn on a belt.

Hematite is often found in deposits with mercury in it. Also of not, many spiritual sites discuss that hematite works to bring mercury (the planet) in balance.

Do you have some magnetite. Thats a cool stone too. Migratory birds have traces of this in them and utilize it for orienting themselves to the North pole. Fascinating stone. Its a good grounding stone to use when you need more than usual grounding but need additional "direction" in your life.