Hematite:

Stone that develops the ability to listen. It soothes, relaxes, purifies, transmits courage and energy in difficult times.

It protects against negative energies and electromagnetic waves.

It is associated with the root chakra. It works on the liver, kidneys, spleen and consolidates iron.

Obsidian:

Stone that protects against negative energies. It is a powerful shield against harmful influences. Acting both physically and spiritually, its black color gives it an advanced degree of consciousness. Renowned for absorbing pain and trauma, it is a liberating stone.

It is associated with the 3rd eye chakra. It works on virile power and sexual vigor.

Onyx:

Stone which has the virtue of healing old physical or psychic traumas which still affect the present life. It increases self-control and helps develop a sense of responsibility. It provides strength and support during times of significant mental or physical stress. It helps with emotional stability and brings harmony by absorbing negativity. It promotes blood circulation.

It is associated with the root chakra. She works on the pancreas and the bones.