Gemology
Gems are precious stones which are mainly 9 gems called 'navratna' in Indian vedic astrology. They are Diamond, Emerald, Pearl, Coral, Yellow Sapphire, Blue Sapphire, Ruby, Hassonite and Cat's eye. In Indian astrology horoscope science, gems are connected to the 9 planets depending on their color and type of energy. Gemology is a science of using gems for curing diseases and for prosperity in life.