User can grow diamonds

Pros:
-user can do this anywhere
-user can user diamonds as power source or sensors
-user can make diamond weapons
-user can make diamond structures

Cons:
-user will bleed easily when growing diamonds from their body
-user can't dictate what the diamonds will do
-user loses control when tired
-diamonds is more likely to grow from around them

Weakness: overuse
User will grow diamonds all over their body with more overuse