Green Onyx: Value, Price, and Jewelry Information Green onyx is an assortment of chalcedony, a microcrystalline type of quartz. What recognizes green onyx is its striking green hue, going from sensitive pastel shades to profound, energetic greens. This shading is ascribed to the presence of copper minerals inside the stone. Its name is derived from the Greek word "onyx," meaning hook or fingernail, attributable to its customary use in making cut diamonds and appearances. The history of green onyx may be traced to several parts of the globe.