From time immemorial, the use of gemstones has been prevalent. There has been interesting stories about the origin of gems in various puranas. They have been an integral part of remedial measures used in Astrology.
Every gem has the power to absorb the radiation which is emitted by a particular planet. Each of the gemstone has different color and luster. Through observation of colors in the prism, we can get seven colors (VIBGYOR).
The other two invisible colors are infra red and ultra violet. The spectrum of total nine colors is associated with nine planets in the zodiac system. If the gem is worn on the consultation of an expert astrologer, it would help in enhancing the positive energy of a particular planet in the horoscope. This is due to the reason that wavelength of colored light which emanate from the nine planets matches with the radiations emanating from each planet's gemstone.
As far as choosing the right Gemstone is concerned, it is better to consult a good astrologer who after looking at various combinations in the individual's horoscope can advice for wearing suitable gem. In general, the stone of ascendant or lagna lord is considered as the best for improving self confidence, health, well being, self esteem and recognition.
All the gems are related with a particular planet in the Zodiac.