Opal is suppose to have great positive effects on the people if Venus is a positive planet but sitting in a malefic house. Benefits: It is said to protect the wearer from negative energies from various celestial bodies and also helps them achieving Wealth, Pride and Wisdom. It also is considered helpful in bringing harmony in Love Relationships. Carats Recommendation: 2-2.5 Carats for children, 3-5 Carats for teenagers, 5-15 Carats for adults (Consult an Astrologer, if required)