Ketu, the South Node of the Moon means a "sign", or a "banner" in Sanskrit. If Rahu is the planet of worldly desire, then Ketu is the planet of otherworldly desire, or spirituality. Ketu represents the spiritual process of evolution, or the refinement of materialization to spirit. Ketu is considered a worldly malefic and spiritual benefice, as it causes sorrow and loss, which ultimately turns the individual to god.

The karakas, or indicators of Ketu are focused intelligence, indicator of liberation, indicator of wisdom, non-attachment, other worldly interests, fantasy, penetrating insight, derangement, carrier of arms and weapons, invisibility and physic abilities.

Ketu's gem is the cat's eye. This Graha is of a Pitta, or fiery temperament. Ketu has the last maturity of all the planets at age 48, when the soul turns to the pursuit of MOKSHA the pursuit of liberation from this world.

The blue sapphire is the gemstone of the planet Saturn and helps to overcome problems related to this planet.

Ketu is often depicted with a gem, or a star on his head, which emits a mystery light. Ketu is said to be a member of the Jaimini lineage of sages, who founded one of the several systems of philosophy of ancient India. There are wonderful myths associated with Rahu and Ketu.

The cat's eye  is the gemstone of the planet ketu and helps to overcome problems related to this planet.

Some aspects of the Rituals for Wearing a Cat'seye
The setting should be of astha dhatu  and the gem should be flawless. The gemstone should be given to the jeweler on the same day, and the ring or a pendant should be made and allow the gemstone to touch the skin.