COPPERAS (Fr. couperose;

See also:

• LAT

Lat. cupri

See also:

• ROSA, CARL AUGUST NICHOLAS (1843-1889)
• ROSA, MONTE
• ROSA, SALVATOR (1615-1673)

rosa. the

See also:

• FLOWER (Lat. flos, floris; Fr. fleur)
• FLOWER, SIB

flower of

See also:

• COPPER (symbol Cu, atomic weight 63.1, H=1, or 63.6, O = 16)

copper)  , green vitriol, or ferrous sulphate, FeSO4.7H2O, having a bluish-green colour and an astringent, inky and somewhat sweetish taste . It is used in dyeing and tanning, and in the manufacture of ink and of Nordhausen sulphuric acid or fuming oil of vitriol (see IRON) . COPPER-GLANCE, a mineral consisting of cuprous sulphide, Cu2S, and crystallizing in the orthorhombic system . It is known also as chalcocite, redruthite and vitreous copper (German, Kupferglaserz of G . Agricola, 1546) . The crystals have the form of six-sided tables or prisms; the angle between the prism faces (lettered o in the figure) being 6o° 25' . When twinned on the prism planes o, as is frequently the case, the crystals simulate hexagonal symmetry still more closely, as in the minerals arag- onite and chrysoberyl . Twinning also takes place according to two other laws, giving rise to interpenetrating crystals with the basal planes (s) of the two individuals inclined at angles of 69° or 87° 56' respectively . The mineral also occurs as compact masses of considerable extent . The colour is dark lead-grey with a metallic lustre, but this is never very bright, since the material is readily altered, becoming black and dull on exposure to light . The mineral is soft (H.=22) and sectile, and can be readily cut with a knife, like argentite; sp. gr . 5.7 .

Analyses agree closely with the

formula Cu2S, which corresponds to 79.8% of copper; small quantities of iron and silver are some-times present . Next to chalcopyrite, copper-glance is the most important ore of copper . It usually occurs in the upper part of the copper-bearing lodes, and is a secondary sulphide derived from the chalcopyrite met with at greater depths; sometimes, however, the two minerals are found together in the same part of the lodes . The best crystals are from St Just, St Ives, and Redruth in Cornwall, and from Bristol in Connecticut . Small crystals of recent formation are found on Roman bronze coins in the thermal springs at Bourbonne-les-Bains . Copper-glance readily alters to other minerals, such as malachite, covellite, melaconite and chalcopyrite . On the other hand, it is found as pseudomorphs after chalcopyrite, galena, and organic structures such as wood; copper-glance pseudomorphous after galena preserves the cleavage of the original mineral and is known as harrisite . Isomorphous with copper-glance is the orthorhombic mineral stromeyerite, a double copper and silver sulphide, CuAgS, which occurs in abundance in the Altai Mountains . (L . J .