Green Onyx & What These Symbolises? the Green Onyx gemstone is a fascinating and engaging stone that has won over many hearts. This semi-precious gemstone is a well-liked option for jewelry designers and gemstone fans alike since it comes in a variety of green hues, ranging from pale pastel green to rich emerald green. Green onyx is a magnificent stone whose unique and delicate patterns are created by the way the stone is framed. Layers of cryptocrystalline quartz are what give onyx, a kind of chalcedony, its characteristic attractive banding and veining patterns. Iron and other trace minerals that are said to be inside the stone give Green Onyx its green hue.