Emerald is a variety of beryl, just like aquamarine, and the green color comes from trace amounts of chromium trapped in the crystal. Due to its popularity as a gemstone, emerald is considered a traditional "Big 4" along with rubies, sapphires, and diamonds.
Fuchsite is a special variety of the mineral muscovite, where chromium atoms have slowly replaced the natural aluminum in muscovite's molecular structure. This resulting soft green mineral was named to commemorate Johann Nepomuk von Fuchs, a German mineralogist.
