June’s birthstone isSmoky Quartz. Smoky quartz is part of the same gem family as amethyst, rose quartz, citrine, and prasiolite. It is among the most prevalent crystals extracted from the earth's crust. Shop Birthstone.com’s Smoky Quartz rings, which are believed to bring balance and stability, detoxing the body while stimulating the immune system. They are the traditional stone of the 21st wedding anniversary.