Gemstones which have colors and properties related to planets are used to enhance power of a weak benefic planet in horoscope.
It should not be used for a planet if its functional malefic or placed in 6,8,12 houses.
If a planet is benefic to native by its ownership of good houses but if it is combust or conjunct rahu-ketu, then its power gets reduced and it wont help the native as much required.
So to enhance its power, a gemstone related to it or colored clothes related to it are used.
When a person cannot find quality gemstone or cannot afford it, then alternate gemstones can be used, which usually give lesser effect than original but are safe to use.
|Gemstone||Planet||Minimum Weight||Metal||Finger||Day||Time||Alternate Gemstone|
|5-METAL||MIDDLE||SAT||EVENING||Amethyst, Lapis |