What is a good place you have a rune scimitar now but your def is low now its 49 and you wanna become mem soon if you get 60 attack your attack is now 59 but is granite armour much better then rune ar

It depends on what your fighting against. Full granite armor (shield, legs, body and helm) gives you the following stats:

ATTACK
stab: 0
slash: 0
crush: 0
magic: -50
ranged: -38

DEFENSE
stab: +201
slash: +204
crush: +187
magic: -11
ranged: +269
summoning: +124



And rune armor gives you these stats:

ATTACK
stab: 0
slash: 0
crush: 0
magic: -65
ranged: -21

DEFENSE
stab: +207
slash:+209
crush: +192
magic: -12
ranged: +205
summoning: +102


So as you can see, it is fairly close. But you are a little better off using rune armor if you are fighting against another melee person/creature. But if you are fighting a ranged, magic or summoning player/creature, you are better off wearing the granite. So it just depends on your situation which is better.