The gem is a very influential and mysterious gem representing the planet 'Rahu', which is considered to be a shadow planet and mysterious in Vedic astrology. Onyx is worn to get auspicious results by removing negative effects such as confusion, mental disturbance, sudden loss and fear of the unknown caused when the position of Rahu planet is unfavorable in the horoscope or doshas such as Angaraka Yoga. Wearing this gem gives a person diplomatic ability, political success, sudden wealth gain, bold decision making and advancement in the field of technology and research. In terms of health, it is astrologically believed to provide relief from stomach problems, gastric, mental stress and infection. Onyx is usually attached to a silver or panchadhatu ring and should be worn on Saturday or during Rahukal, if possible, after receiving the gem from the Guru, otherwise Rahu's seed mantra, Om Ra Rahve Namah, should be chanted at least 108 times and worn on the middle finger of the right hand.
Gemstones are often worn according to the zodiac sign, birth chart and also according to the current dasa. However, it would be better to consult an astrologer once and get the birth chart as per the horoscope rather than just the normal horoscope. Wearing a gem without considering Rahu's karakta, position and aspect or conjunction with other benefic planets (such as eclipse dosha with Sun or Moon) in the horoscope may have adverse effects or increase mental disturbance. Also, since the use of onyx with gemstones of planets opposite to Rahu such as ruby, pearl or muga is considered forbidden, it will be more effective and fruitful to wear this gem only after consulting with a good astrologer, knowing how much weight and how to wear it and when to wear it.