Prehnite Bracelet: The Stunning Green Gemstone Prehnite was called after Dutchmen Baron and Colonel Hendrik Von Prehn, who transported the first of these to Europe in 1783 and was found by mineralogist Abraham Gottlob Werner. It appears in shades ranging from olive green to pale yellowish green. Prehnite may also be clear or translucent and has a Mohs hardness of 6 to 6.5.Many astrologers advise wearing Prehnite Bracelets because it is said to assist with lung, heart, and chest thyroid-related ailments. It is also stated that if a person born under the sign of Libra wears Prehnite Jewelry such as Prehnite Bracelets, Prehnite rings, Prehnite earrings, or Prehnite pendants, they will have great bodily and spiritual benefits.