Effect of the plane of minerals on potions
1-2 duration or strength halved
3-4 duration or strength doubled
5 effect limited to 1 class
1-2 fighter
3-4 ranger
5-6 cavalier
7 paladin
8 barbarian
9-10 magic-user
11 illusionist
12-13 cleric
14-15 druid
16-17 thief
18 assassin
19 monk
20 bard
6 potion becomes permanent, unless already is one in effect
7 potion lasts only 1 round
8 side effect - glow as continual light
9