Emerald is a gemstone colored green by chromium and occasionally vanadium. Mica, the matrix that these gemstones are held, is a group of sheet silicate minerals that are monoclinic and include several closely related materials with nearly perfect basal cleavage. Emerald (being a variety of beryl) is a 7.5 - 8 on the Mohs Scale, and is the birthstone for the month of May.
These rough Emerald pieces have a remarkable variation in color from green so light it borders on white, to a deep green that is nearly black. For the most part however, the stones are a pale, pastel green with bursts of vibrancy. Being a 7.5 to 8 on the Mohs scale means that these are a great tumbling stone, and would be ideal in many different projects!
Emerald is the traditional birthstone for May and is called the "Stone of Successful Love" because it is said to open and nurture the heart; it makes sense that it's associated with the Heart Chakra! The Emerald is considered a very powerful stone in many cultures, being thought of as bringing abundance, prosperity, and good fortune.