If one has a lot of spiritual attainment, then you probably already know you should be careful using this. Focusing spiritual fire through the thunderbolt concentrates energy. A warning label is not included. This is your word of caution.
The Dorje should be used with a bell of similar size. It is held in the right hand and is considered a thunderbolt or diamond that destroys all kinds of ignorance. And like a diamond, is considered indestructible. The thunderbolt scepter is the male principle, the bell the female. These two are the most often used objects on the Vajrayana path. In the hands of a master, these inseparable two signify the unity of masculine power and feminine energy.