Gemstones have been widely mentioned in Vedic literature like the Brihat Samhita, Bhava Prakash, Ayurveda Prakash, Garuda Purana and the Rasa Ratna Samuchaya.The Puranas, Agni Purana and Garuda Purana also have reference of gemstones. Gemstones have healing powers and can remove blockages which are the cause of diseases in the human body. It is said that in order to get maximum effect of gems it should be worn and not just owned unlike Rudraksha beads where benefits of these beads can be obtained by just worship also.
Scientifically, Gemstones are formed because of the chemical reactions and can be broadly classified into two, one is those which are mined and the other those come from the Sea. Those gems which are mined include Diamond, Blue Sapphire, Yellow Sapphire, Emerald, Ruby etc and those which are obtained from the sea include Pearl and Coral. Some of the components of gems are Carbon, Calcium, Aluminum, Manganese, Potassium, Prosperous, Beryllium, Hydrogen etc.
According to the astrological point of view the gemstones are divided into two, one is the navratnas and the second is sub stones. The Navaratnas (9 stones) are Diamond, Emerald, Yellow Sapphire, Blue Sapphire, Ruby, Coral, Pearl, Hessonite and Cat's Eye. There are around 80 substones out of which the main sub stones are Citrine, Amethyst, Rock Crystal, Malachite, Turquoise, Peridot, Tourmaline, Opal, Goldstone,Quartz, Zircon, Agate, Lapis Lazuli, Garnet, Moonstone, Hematite, Load Stone, Malanite/Andradite, Chatiyant Quartz/Tiger Eye, Jade/Jadeite, Onyx, Agate, Sulemani Onyx,Aquamarine, Smoky Quartz, Alexandrite, Blood Stone, Amber, Turmaline, and Rainbow Quartz.
Another mode of classification of Gemstones can be as Hot and Cold. The Hot gemstones include Ruby, Red Coral, Diamond and Cats Eye and the Cold gems include Pearl, Topaz, Blue Sapphire and Gomedh.
