Throughout the many years, a lot of people have regarded semi-precious stones, among the many other gemstones, to exude a beautiful exquisiteness and even a bit of magical powers. As a matter of fact, there are those who have believed that these stones carry mystical powers which could be passed on by the stones to whoever wears it.
For example, a blue sapphire could give the ability to the wearer to stay cool even under pressure. Another would be a red ruby could bestow passion to its wearer. Over the years, people started to assign specific gemstones to the zodiac signs and later on, to the months in a year. People who were born in a particular month were believed to have qualities that resemble the gemstone for that month or the "birthstone" that has been linked to that month.
And then, later on, there was some sort of confusion over which birthstones were actually associated with which month. Even today, there are months which have several birthstones that, over the years, have competed for public acceptance.
In the US, though, the American National Association of Jewelers has a list of the official birthstones for each month, which were adopted in 1912. For January, it was the Garnet; for February, the Amethyst; for March, Aquamarine; for April, Diamond; for May, the Emerald; for June, Pearl; for July, Ruby; for August, Peridot; for September, Sapphire; for October, Opal; for November, Yellow Topaz; and for December, Blue Topaz.
Aside from these modern birthstones, there were many other applied birthstones such as the mystical birthstones, the traditional birthstones and the ayurvedic birthstones.