The meaning for gem found in the dictionary is a precious stone of great excellence. This is then a stone and is of earthly powers of the mother earth, while most of these stones are not gems they just glass and other substances. Since ever the ancient people were hunting for gems and if you look in the Indians and other empires of that time they show that these were a part of there treasury. In those times any gifts that were to be given away would be paid by using these very precious stones.
Since a particular time in history when it was known that all the celebrated Kohinoor went to the British Empire. When the precious material of gems were available to the average man it became his property and to the modern day woman is a must have piece of jewelry. Although seen as a piece of jewel it has a lot of great powers which are known to the humans to substitute for some vital organs. With the powers these stones possess they are good for dealing with reaping riches and also finding thing of various ranges.
The first astrologer to talk about gems was Hora Sara from India which was a dedicated astrologist. The shift from their country to the world was done by other authors who looked like that then copied the subject. But it was really when the modern science was introduced to explain about various chemicals with are in the stones. These gems are also know for there energy.