Mr. Saurabh
Moon is signifying Saturn in 6th house. Moon Saturn combination gives you postponements causing you frustration. Moon is the lagna lord signifying 6th house. So if you wear Pearl you will be prone to sickness or diseases. So Pearl is not suggested.
Yellow sapphire is for Jupiter. Jupiter who is the lord of 10th house (reputaion) is in lagna. But Jupiter is in the star of Mercury lord of 4th and 12th house in 5th house. Jupiter (through his sub lord Mercury) is signifying Ketu in 12th house. So for service matters it is not good. So yellow sapphire is not suggested.
Red Coral is for Mars. Mars is in 11th house. It is good. Mars is in the star of Sun in 6th house (service, success over opponents) and deemed to be in conjunction with Saturn and Rahu who signify Sun in 6th house. So red coral is suggested. But Rahu is more powerful than Mars and Saturn. So if you wear Gomedhikam (Hessonite Garnet) for Rahu it will act more than Mars and Saturn. So Gomed is suggested by me. It is your choice either Red coral or Gomed.
Good Luck
JVS Rao (KP system follower)