Orcyiogne- the missive varieties only translucent on the edges, or 

 opaque. Colour of the streak pale-green. Brittle, in- 



s ,~ ' clining to sectile, and easily frangible. 



Chemical Character*. Before the blowpipe it decre- 

 pitates and becomes black, and is partly infusible, part- 

 ly reduced to a black slag. 



CoHititucnt Part*. Copper, 



Carbonic Acid, 



Oxygen, 



Water, 



An. Mus. t. xx. p. 8. 



Geognottic Situation Occurs principally in veins 

 that traverse primitive, transition, and secondary rocks. 

 Geographic Situation Occurs at Sandlodge, in 

 Mainland, one of the Shetland Islands, in veins that 

 traverse red sandstone, in which it is associated with 

 grey copper, copper- pyrites, and brown iron-ore; 

 at Landidno in Caernarvonshire; and in various mines 

 in other parts of the world. 



fhc^y. 



56.10 

 21.25 

 14.00 

 8.75100.00 



Compact 

 Miltchitc. 



SECOND SUBSPECIES. 



COMPACT MALACHITE, Jamtton. Dichtcr Malacb.it, 

 Werner. 



External Character! Colour intermediate between 

 emerald-green and verdigris-green ; but in general in- 

 clining more to the fir>t. Colours often disposed in 

 concentric delineations, and varied with dark-coloured 

 dendritic marking!. Occurs massive, disseminated, 

 and in membranes ; most frequently reniform and bo- 

 tryoidal, frequently tuberose, sulactitic, fruticose, cel- 

 lular, and amorphous ; also in distinct concretions, 

 which are sometimes extremely delicate and scopiform 

 fibrous ; more frequently thin lamellar, or large, coarse, 

 and small angulo-granular ; and sometimes crystallized 

 in oblique four-sided prism*. External surface of the 

 particular shapes generally rough and drusy, scldomer 

 smooth, and then it is shining and glistening. Sur- 

 face of the distinct concretions apparently covered with 

 a greenish-white film. Internally it passes from glis- 

 tening through glimmering to dull, but roost common- 

 ly glimmering, and the luitre silky. Fracture small 

 and fine grained uneven, which sometimes passes into 

 small and flat conchoida), and even. Fragments inde- 

 terminate angular, and rather sharp-edged. Opaque. 

 Rather brittle, and easily frangible. Streak pale-green. 

 Chemical Character! and Conttituent Parti nearly the 

 same with the preceding subspecies. 



Gfognnitic Situation. \l occurs in veins, which tra- 

 verse primitive transition, and secondary rocks. 



Geographic Situation Europe. \n the copper mines 

 of Huel-Carpenter and Hue)- Husband, in Cornw.-.ll ; 

 in the copper-mines of Aardal in Norway ; and in 

 many other mines on the Continent of Europe. 



Ana In the mines of Kolwyan, Gamasherk, Turja, 

 fie. in Siberia, where the most beautiful and largest 

 specimens of this mineral are met with, along with 

 tilf-ore, red copper-ore, brown iron-ore, copper-glance 

 or vitreous copper, blue copper, copper-green, white 

 lead- spar, brown-spur, ironshot quartz, hornstone, &c. 

 It i also met with in different parts of China. 



Lie*. It was formerly esteemed as a precious stone, 

 and was cut into ornamental forms of various descrip- 

 tions. Even at present it is highly prized, and is cut 

 into consoles, candlesticks, snuff-boxes, and other simi- 

 lar articles. Where it occurs in quantity, it is smelted 

 as an ore of copper, and is sometimes used at green 

 pigment. 



MINERALOGY. 511 



BROWN COPPER. Analysis of a new species of Orcytogno. 



Copper-ore, by Dr. Thomson, Phil. Trans, for 181*. "^ , 



Eternal Characters Colour, when pure, dark Brown 

 blackish brown ; but very generally intermixed with copper. 

 malachite and red copper-ore, so that the colour ap- 

 pears a mixture of green, red, and brown, sometimes 

 one and sometimes another prevailing. Small green 

 veins of malachite likewise traverse it in different 

 directions. Occurs massive, with numerous imbedded 

 small rock-crystals. J.nstre glimmering and resinous. 

 Fracture small conchoidal, and sometimes inclining to 

 foliated. Soft, being easily scratched by the knife. 

 Sectile. Streak reddish- brown. Specific gravity, 2 620, 

 Thomson. 



Chemical Characters. It effervesces in acids, and 

 dissolves, letting fall a red powder. The solution is 

 green or blue, according to the acid, indicating that it 

 consists chiefly of copper. 

 Constituent Parti. Carbonic Acid, 16.70 

 Per-oxideofCopper,60 75 

 Per-oxide of Iron, 19.50 

 Silica, . . 2.10 

 Low, . . 09510000 

 Thornton, in Phil. Trans, for 1814. 

 Geognoslic Situation It appears to occur in nests 

 in primitive rocks, which are of greenstone, or some 

 similar rock of the primitive trap series subordinate to 

 mica-slate. It is associated with malachite. 



Geographic Situation In the peninsula of Hindos- 

 tan, near the eastern border of the Mysore country. 



GENUS III. OLIVENITE. 



Oliven-Malachit, Mahs. 



OLIVEXITI. 



Many axes. Cleavage prismatic, tessular; ttreak 

 blue, green, brown. If streak green or blue, the spe- 

 cific gravity is 4 and more, or 3 and less. Hardness 

 from 2.5 to 5. Sp. gr. from 2.8 to 4.6. 



This genus contains four species, viz. 1. Prismatic 

 Olivenite, or Phmphat of Copper; 2. Di-prismatic 

 Olivenite, or Lenticular Copper; 3. Acicular Olive- 

 nite ; 4. Hexahedral Olivenite, or Cube-Ore, Ata- 

 camite. 



I. PRISMATIC OLIVEVITE, or PHOSPHAT OF COPPER, Prismatic 

 Jameson. I'rintnatischer Oliven-M.ilachit, Moht. ('livenite. 



I'n-tn = 11*)*. Cleavage the same. Streak eme- 

 rald green. Hardness = 5. Sp. gr. = 4.0 4.3. 



External Character* Princijal colour emerald-green, 

 which passes into blackish-green ; externally, some- 

 times greenish-black. Occurs massive, in imperfect 

 reniform masses, with a very drusy surface, and in 

 coarse fibrous distinct concretions, which are straight 

 and scopiform. Crystals small and very small, super- 

 imposed and in druses. Externally shining ; internal- 

 ly passes from shining, through glistening, to glim- 

 mering, and the lustre resinous, inclining to pearly. 

 Fracture splintery. Fragments wedge-shaped splintery, 

 or indeterminate angular, and rather blunt-edged. 

 Opaque. Streak verdigris-green. Brittle and easily 

 frangible. 



Chemical Characters. On the first impression of the 

 heat it fuses into a brownish globule, which, by the 

 further action of the blowpipe, extends on the surface 

 of the charcoal, and acquires a reddish-grey metallic- 

 colour. 



Conttituent Parti. Oxide of Copper, 68. 1 3 



Phosphoric Acid, 30.9599.08 

 K/aproth, Beit. b. iii. s. 201. 



