Black Moonstone

Black Moonstone
Helps with financial security
Improves concentration 
Increase stamina
Helps to feel more grounded in or out of a love relationship
Provides general psychic protection
You will often see streaks of peach moonstone with the black moonstone.  This is very common  and the black moonstone has a variety of shades from a light gray to a dark gray.  
From Madagascar
 
These are priced by weight but not necessarily by size.