Pendulums have been used as a divination tool technique for seeking answers. Also known as dowsing, the pointed end of the crystal is there to guide us by its changing direction for simple yes or no questions. Think of the pendulum as the receiver and transmitter of energy from the divine. 
Pendulums can also be used to clear any negative energy in a space. 
This divination tool is for yes no answers and when you work with your pendulum you can decide which direction is yes and which is no.