Dear Ananth,
In this horoscope Moon's exaltation house is 5th and Moon is 7th lord.Moon is associted with Saturn and Mars in 9th.For him to have good results of 5th and 7th houses (love,marriage,mental capacity,good relationships etc etc..)and neutralise the slow and harsh effects of Saturn and Mars, a pearl is the best remedy.Other gems are not recommended as per the planetary positions.
USR