Olivenite is a copper arsenate mineral. Its most notable feature (which leads to its name) is the typical olive green color. The color may vary in shade from blackish-green in the crystals to almost white in the finely fibrous variety known as woodcopper. Olivenite normally occurs as globular aggregates of acicular crystals. Olivenite may also be found as rare fibrous masses and sheets that look like a sheet of paper. This variety of Olivenite is called Leucochalcite. It is similar in form to a variety of Actinolite called "mountain leather".
The mineral was formerly found in some abundance, associated with limonite and quartz, in the upper workings in the copper mines of the St Day district in Cornwall, England. It has also been found in Utah, Nevada, and Tsumeb, Namibia. It is a mineral of secondary origin, a result of the oxidation of copper ores and arsenopyrite. Olivenite's olive green color and bright luster make it a popular mineral specimen.
Item # 1OLV09163351
Olivenite Acicular Crystals from St. Day, Cornwall
Here's an excellent Old Stock display specimen of Olivenite. This specimen was procured from a mineral dealer in Hendersonville, North Carolina. It is from a 1970's collection. This is a rare classic specimen of an excellent olive green acicular pocket of Olivenite from St. Day, Cornwall, England.
This specimen weighs 1.4 oz (41g) and measures 1.5 x 1.2 x 1.1 inches (39 x 30 x 29mm)