Find Weakness

Information 
Sense the weakest part of the subject. Can be cast on any part of a large object; you would not have to cast it on a whole city wall, for instance, but could check one yard of wall at a time. Of course, many subjects will have no special weakness. 
This spell can be used to troubleshoot complex objects; a defect that prevents a machine from working usually qualifies as its weakest part.

Cost: 1, or 1 per yard radius for a large object. Double this cost if the subject is alive. 
Time to cast: 2 seconds. 
Prerequisites: One spell from each of the four elements.

Item 
Jewelry.  
Energy cost to create: 100.