CLINOCLASITE  , a rare

mineral consisting of the basic copper arsenate (CuOH)3AsO4 . It crystallizes in the monoclinic 1 The word " climb " (O.E. climban), meaning strictly to ascend (or similarly descend) by progressive self-impulsion, with some apparent degree of laborious effort and by means of contact with the surface traversed, is connected with the same root as in " cleave " and " cling." For Alpine climbing, &c., see MOUNTAINEERING . system and possesses a perfect cleavage parallel to the basal plane; this cleavage is obliquely placed with respect to the prism faces of the crystal, hence the name clinoclase or clinoclasite, from Gr . KAivew, to incline, and Khav, to break . The crystals are deep blue in colour, and are usually radially arranged in hemispherical groups . Hardness 22-3; specific gravity 4.36 . The mineral was formerly found with other copper arsenates in the mines of the St Day district of Cornwall . It has also been found near Tavistock in Devonshire, near Sayda (or Saida) in Saxony, and in the Tintic district of Utah . It is a mineral of secondary origin, having resulted by the decomposition of copper ores and mispickel in the upper part of mineral veins . The corresponding basic copper phosphate, (CuOH)3PO4, is the mineral pseudomalachite, which occurs as green botryoidal masses resembling malachite in appearance .