Apart from a precious and beautiful stone, gems play crucial role in Vedic astrology. Vedic astrology means Science of lights. As we know that the light is a construct of seven different rays which are Violet, Indigo, Blue, Green, Yellow, Orange, and Red. We can also see rays of these colours in rainbow. In the ancient Indian text, the "KURMA PURANA", the seven planets are to be seen as condensations of the seven different coloured cosmic rays. It was understood that on our planet Earth the greatest condensation of the cosmic rays are found in natural gem stones. Different gem attracts different ray thus used for different purpose. These gems can also be used for decreasing malefic effect of miss-positioned planets in somebody's birth chart.