Pendulums are used as a divination tool and are often used as tools for spiritual healing and inner growth. Pendulums help us to reach our through our phsyical senses and delve into our spiritual ones.
Onyx is a strong stone. It gives strentgh to it's owner. Onyx will help to center your energy and give you focus during times of confusion. It will bring balance to the whole. It helps with foreordination and becoming a master of your own choices and furture.
Onyx also holds on to the secrets from the past. It can help you in past-life work and help you heal from old traumas.
Onyx will help to blend the yin and the yang within you. It holds onto the dual sides and energies of your personality.