Chrysoprase

Chrysoprase or chrysophrase is a gemstone, variety of chalcedony that contains small quantities of nickel. It is a beautiful green stone which varies from a pale green to apple green and on to a darker, deeper green color. The word chrysoprase comes from the Greek chrysos means 'gold' and prason, means 'leek'. It is one of the highly prized members of chalcedony mineral group.

Chrysoprase Information
Rather unusual, Chrysoprase gets its color from very small amounts of nickel. Other stones like emerald, gets their color from mixing chromium in it.
Other rock crystal such as amethysts is transparent, whereas this gem is normally semi-transparent. Chrysoprase has a hardness rating of 7, on the Moh's scale, and a gravity of 2.65 to 2.66. It is found in beads and cut form.
It contains Cryptocrystalline, which means that it is composed of crystals which are so fine that they cannot be seen under normal magnification as distinct particles.
Like other gemstones, it is found with poor color quality, flaws, inclusions but what we see in gemstone jewelry is an apple green or deeper green with no flaws of any kind.
It is used as the birthstone for May month and for Gemini' or Libra. These stones have metaphysical properties like compassion, acceptance and grace. The stone is said to increase fertility, increase energy levels and is accepted as a soothing stone. It calms over excitement, takes the heat out of situations, and inspires tolerance. It is also used for Spiritual protection. Ancient historians believe that it helps in improving eyesight.
It is found in Queensland, Australia and some parts of Austria, Brazil and others. It is found embedded in serpentine rock.
It is marketed as "Australian Imperial Jade".
Folklore
Chrysoprase had its medical usability, as it contains high alkalinity.
Astrologers link this stone with planet Mercury and Venus. Greek Sailors used to wear amulets of it to prevent drowning. If someone was lost and could not be found, the stone was blamed for it.