Chalcedony is composed of two types of silica minerals and is semi-transparent to translucent. In its broad sense, Chalcedony refers to a wide variety of gemstones, such as agate, Aventurine, carnelian, Chrysoprase and Chrysocolla.
Chrysoprase, which means golden leek, goes from apple green to deep green and consists of microscopic crystals (=cryptocrystalline) and nickel, the latter being responsible for its color. It is one of the oldest known gemstones and is sometimes confused with jade.
Chrysocolla, which means gold glue, was used (as a glue) to solder gold. It lends its vivid cyan blue color from the presence of copper oxidation. The mineral is sometimes confused with turquoise as it exists in similar color range, namely powder blue, green blue and green with brown.