Emerald is a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium and sometimes vanadium. Beryl has a hardness of 7.5–8 on the 10 point Mohs scale of mineral hardness. Most emeralds are highly included, so their toughness (resistance to breakage) is classified as generally poor.
Famous quotes containing the word emerald:
“Well, Mr. Thornton, you are a wonder. It looks the way all Irish cottages should and so seldom do. And only an American would have thought of emerald green.”
—Frank S. Nugent (19081965)