February's birthstone is amethyst. Some also include onyx but I will concentrate on the amethyst.
Amethyst is actually a quartz which must be purple in color. There is a chemical reaction which causes this and if you are interested there is information out there for you to consult, it was a bit over my comprehension. This quartz color can vary from a pale lilac to a deep, deep purple. You can find amethyst all over the world.
Not only is it the birthstone of February, it is also the zodiac stone of Pisces (February 19 to March 20) and the stone for wedding anniversaries 4th, 6th, and 17th. The amethyst is the gemstone of the state of South Carolina and Ontario Canada. It is a symbol of peace of mind and sincereity.
From my reseach, it's properties are something we all could appreciate, and it has many. It is said to prevent intoxication and was used in chalises for this purpose. As it resembles the sky at dusk, many believe that it transitions you easily into sleep for insomnia and into the dreamworld, keeping away nightmares.
Purple is the color of spirit and spiritually the amethyst transitions you to a place of consciousness which is deeper. It gives the wearer gentility, courage and happiness. It also helps those in stress and grief. And if this is not enough, add protecting crops, courage in battle, good fortune in hunting, friendship and purity.