Brief Description: Its name derives from the Greek word malachi, molochi = mallow, because of its green colour. In the past, they used the synonyms: chrysokolla (according to Theophrastus and Dioskourides), pseudo-emerald (according to Theophrastus) and molochite (according to Plinius). Its chemical formula is Cu2CO3(OH)2 and it belongs to the category carbonate minerals. Its lustre is pearly, vitreous (in the crystal varieties), silky (in the fibrous varieties), dull. It is found in transparent, semitransparent and opaque form. It has green colour (that ranges from bright green, dark green to black-green). Its hardness is 3½ - 4 and its specific gravity from 3.9 to 4.5, while its fusibility is 3. Crystal system: monoclinic. Its crystal form is rare and its crystals are prismatic or capillary. It can also be found in pseudomorphic crystals by azurite. It usually occurs in radial needles that form botryose or stalactite-like aggregates, but also as encrustations. It effervesces with dilute hydrochloric acid. It is found in the oxidation zone of copper deposits with azurite, chrysokolla, cuprite, copper, ferroxides etc. 
Bibliography: Ευρετήριο ορυκτών ΑΠΘ στην ιστοσελίδα http://www.geo.auth.gr/106/az_gr.htm Τσιραμπίδης Α. Ο ορυκτός πλούτος της Ελλάδας. Εκδόσεις Γιαχούδη Θεσσαλονίκη, 2005, σελ. 391. Berry, L.G., Mason, B. and Dietrich, R.V. (1983). Mineralogy. W. H. Freeman and Company, San Francisco, 561 pp. Σαπουντζής, Η. και Χριστοφίδης, Γ. (1985). Ορυκτοδιαγνωστική. University Studio Press, Θεσσαλονίκη, 241 σ.