April's birthstone is a pure, clear stone: If you step into a gold-and-diamond jewelry store, they will of course tell you that Diamond is the birthstone for April. However, Rock Crystal (clear quartz) is also one of April's birthstones, and outside the US, it's more popular than diamond, for April's birthstone. Shop genuine rock crystal (clear quartz) gemstone beads, points and pendants, as well as sparkling cubic zirconias set in sterling silver, and Swarovski crystal beads, pendants and findings in diamond-clear Austrian crystal. Herkimer Diamonds are water-clear double-terminated quartz crystals, considered to be very powerful in the world of crystal healing. They are also beautiful for April birthstone jewelry.