The birthstones by month are garnet for January, amethyst for February, aquamarine and bloodstone for March, diamond for April, emerald for May, pearl, moonstone, and alexandrite for June, ruby for July, peridot for August, sapphire for September, opal and tourmaline for October, topaz and citrine for November, and tanzanite, zircon, and turquoise for December. You will find the full list of birthstones by month in this article.