The history of birthstones

Now everyone knows his birthstone, but maybe not all the people know why. What we just know is that every month has its stone. Now I will tell you something about it.
The idea of birthstones can be traced back to the breastplate of the Aaron in the Bible in the book of exodus. It is that a gemstone was assigned to each month of the year. The breastplate is a religious garment that set with twelve gemstones which represent twelve tribes of the Israel. The gemstones are divided into four rows of three.
The works of the Flavius Josephus and St. Jerome had combined the 12 stones in the breastplate and the 12 signs of the zodiac together. They thought that the stone had special power that associated to the corresponding astrological sign. One who wears the stone in the right time can get therapeutic or talismanic benefits.
Now the concept of the birthstone is based on the astrological model. 12 different gemstones assigned to the signs of the zodiac. Month 1-3 is Sardius, topaz and carbuncle. Month 4-6 is  emerald, sapphire and diamond. Month 6-9 is ligure, agate and amethyst. Month 10-12 is beryl onyx and jasper. This is more likely the Vedic astrological tradition of India.
This is a brief introduction of the birthstones and their history; you can know the origin of them after reading this general state.