What factors affect the size of the crystals that form as magma cools?

Time. the more time its under the larger the crystal gets The size of the crystals depends on several factors. The rate at which the magma cools, the amount of gas the magma contains, and the chemical composition of the magma all affect crystal size.

He want to contact the red cross/red crescent because they are the main non profit organization that deals with disasters around the world 

There is no map, maybe give the link, it may be b