Need help finding the rules on magically reinforcing objects

[mehs]

So im trying to magically reinforce a gem so that it is harder to break. I can find rules on increasing hardness of armor/weapons (magic arms and armor get bonus per +x, reinforce armaments doubles) and i can find rules on reinforcing walls. Are there any rules on price to reinforce objects in general?

[Darth Ultron]

The spell Hardening is permanent and can increase the hardness of an item by one point per caster level.

Augment Object only last a day per level, but gives adds +20 to the break DC of the object and doubles its hardness and hit points. An augmented object also gains a saving throw against spells when unattended as if it were a magic item (save bonus equals 2 + half the caster level).

[mehs]

The spell Hardening is permanent and can increase the hardness of an item by one point per caster level.

Augment Object only last a day per level, but gives adds +20 to the break DC of the object and doubles its hardness and hit points. An augmented object also gains a saving throw against spells when unattended as if it were a magic item (save bonus equals 2 + half the caster level).

Pathfinder dude. Pathfinder

[unseenmage]

Luckily half their advice was PF compatible (http://www.aonprd.com/SpellDisplay.aspx?ItemName=Hardening).