510 



MINERALOGY. 



Orcytogno- 

 tj. 



Blue cop- 

 per. 



GrognoilicSilnaliun. Both subspecies usually occur 

 _ _ together, nnd they frequently pass into each other. 



Geographic Situation. It occurs in Cornwall, along 

 with olivenite. 



MILICBITI. GENUS II. MALACHITE. 



Kalo Malachit, Molts. 



Three axes. Cleavage prismatic. Streak blue ; 

 green ; very pure. Hardness=3.5, 4.0. 8 p. gravity 

 = 3.5, - 3.7 



This Genus contains two species, viz. 1 Blue Copper 

 or Prismatic Malachite, and 2. Common or Acicular 

 Malachite. * Brown Copper. 



1. BLUE COPPER or PRISMATIC MALACHIT E. Jame- 

 son. Prismatischer Kalo-Malachit, Mohf. Kupferlazur, 

 Jf 'enter. 



Prism. i= . Cleavage uncertain. Streak blue. 



This species is divided into two subspecies, viz. 

 Radiated Blue Copper, and Earthy Blue Copper. 

 * Velvet Blue-Copper. 



FIRST SUBSPECIES. 



Radiated RADIATED BLUE COPPER, Jameson. Feste Kup- 



blue cop- ferlazur, Werner. 



External Cltarnclers. Principal colour azure-blue, 

 which often passes into bhcki.sh-b'ue, seldomer into 

 Berlin-blue and smalt-blue. Occurs massive, dissemi- 

 nated, in plates, in crusts ; also globular, botryoidal, 

 reniform. stalactitic, and cellular ; in prismatic distinct 

 concretions, which are straight, narrow, scopiform, and 

 stellular, and these are again traversed by others which 

 are curved lamellar. Sometimes there is a tendency to 

 granular concretions. Very frequently crystallized. Ge- 

 nerally occurs in oblique four-sided prisms, rat her acute- 

 ly bevelledontheterminsl planes.antl the bevelling planes 

 set on the acuter lateral edges. Crystals small and very 

 small, seldom middle-sized. Sometimes aggregated in 

 globular and botryoidal forms ; other crystals occur in 

 druses, or singly superimposed. External surface of 

 the particular external shapes drusy and glimmering ; 

 that of the crystals sometimes smooth anil splendent. Ex- 

 ternally the crystallized varieties are shining, but the 

 massive and particular external shapes dull. Internally 

 shining and glistening, and lustre intermediate between 

 vitreous and resinous. Fracture small and imperfect 

 conchoidal. Fragments of the prismatic or radiated 

 varieties wedge-shaped ; those of the foliated and con- 

 choidal splintery. Crystals translucent, passing into 

 semi-transpareni, sometimes only translucent on the 

 edges. Colour becomes lighter in the streak. Brittle, 

 and rather easily frangible. 



Chemical Characters. It is soluble with effervescence 

 in nitric acid. 



Chcssy. 

 50.00 

 85.00 

 12.50 



6.50100.00 

 p. 3. 

 vrins 



that traverse primitive, transition, and secondary or 

 floetz rocks : in smaller quantity and less frequently in 

 beds. 



Geographic Situation Occurs at Leadhills in Lan- 



Constituent Parts Copper, 



Carbonic Acid, 



Oxygen, 



Water, 



Vauquelin, An. du Mus. t. xx 

 Geognoflic Situation. This mineral occurs in 



along with malachite and brown iron- 



arkshire, and Wanlockhead in Dumfriesshire ; Huel- O j 

 Virgin and Carharrack in Cornwall. 



SECOND SUBSPECIES. 

 EARTHY BLUE COPPER, Jameson Erdieer Kupfer- r, . 



i IST c*ar(h v 



lazur. Werner. b:ue ^ 



External Characters Colour smalt-blue, which per- 

 sometimes inclines slightly to sky-blue. Massive, of- 

 ten disseminated, thinly coating, and rarely small bo- 

 tyroidal. Of friable consistence, and composed of dull 

 and fine dusty particles that soil very faintly, and 

 which are more or less cohering. 



Geognostic and Geographic Situations Occurs in 



small quantity, and usually accompanied with mala- 

 chite and copper-green. In Silesia, found incrusting 

 bituminous marl- slate; in Thuringia, coating varieties 

 of the old red sandstone ; and in Siberia, disseminated 

 in sandstone. 



* VELVET-BLUE COPPER, Jameson Kupfersamm- 



terz, Werner. Kupfersammterz, Kanlen, Tabel. s. 62. 

 Id. Hof. b. Sv. s. 143. 



External Characters Colour intermediate between 

 smalublue and sky-blue, and sometimes passes into 

 sky-blue. Occurs in very small and delicate capillary 

 crystals, which generally form a velvety crust, and are 

 seldom aggregated in balls. Externally and internally 

 lustre glistening and pearly, or silky. Very soft. 



Gengnostic and Geographic Situations A very rare 



mineral, and has hitherto been found only at Oravicza 



in the Bannat, 



stone. 



2. COMMON OR ACICULAR MALACHITE t, Jameson. Common 

 Malachit, Werner. malachite. 



Prism =r . Cleavage uncertain. Streak green. 



This species is divided into two subspecies, viz. 

 Fibrous Malachite and Compact Malachite. * Brown 

 Copper. 



FIRST SUBSPECIES. 



FIBROUS MALACHITE, Jameson. Fasricher Malachit, p.., 



fjr " i orous 



Werner. malachite. 



External Characters Most common colour perfect 

 emerald-green, sometimes inclining to grass-green, and 

 sometimes to dark leek green. Seldom massive, some- 

 times disseminated, tuberose, stalactitic, reniform, bo- 

 tryoidal, fruticose, most frequently as a coating, also 

 in fibrous distinct concretions, which are delicate and 

 scopiform or stellular, and collected into others which 

 are large, coarse, and sometimes longish granular, or 

 wedge-shaped. Frequently crystallized; and the fol. 

 lowing are the figures which have been observed: 



1. Rather oblique four-sided prism, bevelled on the 

 extremities, the bevelling planes set on the obtuse late- 

 ral edges. 2. The preceding figure truncated on the 

 obtuse lateral edges, which thus forms a six-sided 

 prism, in which the bevelling planes are set on two 

 opposite lateral planes. 



Crystals generally short, capillary, and acicular. 

 When very short, they form velvety drusy pellicles ; 

 and when longer, they are scopitbrmly aggregated. 

 Internally intermediate between glistening and glim- 

 mering, and the lutre pearly or silky. Fragments 

 wedge-shaped and splintery. Crystals translucent, but 



f The name of the species is derived from the word /u.a^*%iz, malva, from the resemblance of its green colour to that of the marsh. 

 mallow. The Greek word is sometimes corruptly written ptl>x<i, whence Pliny has derived the term moloc/iites : " Non translucet mo- 

 lochites, spissius vixens et ciassius quam smaragdus, a colore malvse nomine accepto." 





