Our great sages and polymaths perfected the art and the science of astrology in ancient times. As such astrology has witnessed continuous development and proliferated into many branches and divisions, all of which are equal in importance. Gemmology or the scientific and ethnic study of gemstones is an important and integral part of applied astrology. It is so popular among the Indian public that no one is certain as to when it had actually come into practice. Use of precious gems and stones has been an ancient practice in India. Some people believe that it is one or two thousand years old science while others maintain that science and art of gemmology originated about five or ten thousand years ago. Scriptural evidences however show that concept of gemmology is as old as the creation itself. A very famous hymn says:

Apart from many kinds of weapons, Lord Vishnu bears Kaustubha Mani (a gem named Kaustubh) on his chest. This gem is most dear to Him. This hymn shows that even before the whole universe came into being, Lord Vishnu did have an existence and the gem Kaustubh also existed along with Him.

During medieval period also, various scholars shed light on the science of gemmology. They authored many great scriptures as well. Acharya Varahmihir was the most prominent of those great scholars. A scripture Vrihat Samhita written by Varahmihir still has a wide recognition among the gemologists. It has a whole chapter, Ratnadhyay devoted to the comprehensive description of the gemstones. Among Puranas, Agnipurana contains exhaustive description about gemmology.

In modern era also, countless scholars are continuously working with dedication in the field of gemmology. Thanks to their efforts that the science of gemmology is scaling new heights.

In the present discussion, we shall try to find out:
1) What are gems?
2) Is wearing a stone mere superstition or it really bears fruit?
3) What is the chemical composition of the gemstones?
4) In what circumstances should the gemstones be worn?
5) In which circumstances should the gemstones not be worn?
6) Which person should wear which stone?
7) Which person should not wear which stone?
8) How did the gemstones originate as per the religious scriptures of India?
9) Stones of which planets can be worn together?
10) Do the gemstones have medicinal use also? What is the gemopathy?
11) What are the 6 jewels and how did they originate?
12) How can the gems and jewels be classified?
13) What is the total number of the gemstones and what are their names?

Let us first try to understand what a gem is. We are all familiar with the adjective use of the words gem, jewel etc. Any dear one or prominent one is addressed as a 'gem' or 'jewel' in colloquial terms. Similarly anything that is rare in qualities, availability or virtues is also referred to as a gem or jewel. But literally, a gem is something that has been dug out from earth or deep sea and has many rare but miraculous qualities. A gem is unique and often rare because of its specific composition. It may differ in effects, colour, tinge and hues. Similarly, prices of the same stone, may also vary with slight difference in appearance.

All the gems and jewels however have one thing in common i.e. their hue. A jewel has a distinct hue that differentiates it from the rest of the commonly available materials. Our learned sages have described eighty-four different kinds of gems and jewels among which nine are most important. Because of it, titles like Navratna (nine most precious gems) came into practice. But being superior in designation does not mean that the remaining seventy-five gems are totally worthless or not in common use. They too have their distinct appearance, beauty, hues and effects and are important accordingly. Their uses are also wide and varied such as personal beautification, adornment, house building, idol construction, exhibition of wealth and luxury etc. Thus, there are totally eighty-four gems and jewels of which nine are main (or more popular) and seventy-five are less popular.

Though there are different classes and categories of the gems that distinguish them from one another, but gemstones belonging to the same category resemble one another to a great extent with slight variations in hues and appearance.

Some of the stones have uniform colours like yellow, green, red, blue, violet, black or golden while many have a mixed hue of different colours. Each gem has its own importance. Regardless of category, a gemstone is priced according to its beauty, brilliance, appearance and purity. Lacking these qualities, a gemstone has no worth in the eye of a connoisseur. Diamond, sapphire, topaz, emerald and ruby belong to the category of most precious stones. All of them have their distinct chemical composition and are priced accordingly.

Thus now we may say that-
1) Gemstones are harder than ordinary stones.
2) Gemstones are more brighter and smoother than ordinary stones.
3) Distinct hue is the main feature of a gemstone.
4) Usually, each gemstone radiates rays similar to its colour.
5) Radiation effect of the gemstones is controlled and affected by the light and rays of the planets and group of stars situated in space.
6) Gemstones have both positive and negative capacities.
7) A particular gemstone prescribed for a particular planet receives the rays from that planet and facilitates them to enter our body.