Gem therapy recommendation or use of gemstones proves to be the most powerful and helpful remedy to improve planetary effects in our life. Gemstones are suggested by expert astrologers based on your natal chart & present Dasha or transit conditions to strengthen weak planet as positioned in natal chart.
When Jupiter though beneficial , the person will suffer from lack of joy and well being, lack of self confidence and lack of faith. We will be always pessimistic and we will feel narrow and constricted with no clear purpose in life. There may be depression,anxiety, melancholy, and self pity. There may not be material and financial prosperity in life. There will be little progeny happiness. For women, husband will be a cause of sorrow or hardship.
Physically there will be poor vitality, weak immune function, low fat or body weight, poor liver and pancreas function, and weak absorption . Often there will be chronic disease and poor functioning of the nerves and glands. Positive health and vitality will be rare.
Jupiter is worst when it is debilitated in Capricorn, when aspected by malefic like Saturn, rahu, ketu and mars and when it is located in difficult houses like sixth, eighth and twelfth.
Jupiter is a benefic planet for Aries , Cancer, Leo, Scorpio, Sagittarius and Pisces Ascendants. Its best position is Cancer which is its sign of exaltation. The best houses for Jupiter is ascendant, 5th house , 9th house, 10th house and 11th house. Common belief among astrologers
That if Jupiter is placed in ascendant then it can neutralize 100 negative combinations in the chart. If Jupiter is in 11th house it will bestow immense wealth of the person.
Strengthening Jupiter in these situations will increase its positive qualities of joy, creativity and intelligence and wisdom manifold , even if they are not lacking in the person.
The main gemstone for Jupiter is a yellow sapphire gemstones. It should be set in gold and worn on the index finger of the right hand. It should be at least 3 carats in size or ( 5 Rattis).
Yellow Topaz is a substitute of almost equal value ( it should be at least 4 carats in size).
Citrine is weaker and should be worn as a large ring ( 7 carats) , a pendant or strand. Yellow Zircon can also be used.
Such gems should be put on first on a Thursday, preferably when the Moon is waxing and when Jupiter is in its own sign like Sagittarius or Pisces or in its exalted sign. It is best if Jupiter is conjunct or in an angle from the Moon. Alternately a good muhurta must be chosen.
Gems for Jupiter are generally the most safe and balanced of all stones, as Jupiter is the best natural benefic in a chart. However it must be avoided if it is debilitated in the birth chart. It should also be avoided when Jupiter is the lord of malefic houses in the chart in case of Taurus or Libra ascendants.
Reference : Astrology of the Seers by David Frawley.