ATELESITE. 

 than emerald, sometimes blackish-green. 

 Translucent or nearly transparent, soft and 

 brittle, with an apple- green streak. Lustre 

 vitreous. H. 3 to 3-5. S.G. 4 to 4-3. 



Comp. Muriate of Copper, or CuCl + 3 Cu 



H = oxide of copper 55-8, chloride of cop- 

 per 31-5, water 12-7 = 100. 



Analysis by Bibra, from Algodan Bay, 

 in Bolivia : 



Oxide of copper . 



. 56-00 



Copper 



. 14-54 



Chlorine 



. 1612 



Water 



. 12-13 



Silica .... 



. 0-91 



99-70 



BB tinges the flame bright green or blue, 

 and gives off" fumes of muriatic acid ; yields 

 a bead of copper on charcoal. 



Soluble without effervescence in nitric 

 acid, and communicates instantaneously a 

 fine blue colour to ammonia. 



Localities. Chiefly at Los Eemolinos and 

 Solidad, in Chili; in Bolivia, in the dis- 

 trict of Tarapaca; and at Tocopilla, 16 



gues north of Cobija. Also in the iron 

 mines of Schwartzenberg, in Saxony; on 

 some of the lavas of Vesuvius ; in South 

 Australia, and in small rhombic prisms 

 on Malachite and Quartz, at the Mala- 

 chite mines in the Serra do Bembe, near 

 Ambriz, on the West Coast of Africa. 



What was originally called "Peruvian 

 jreen sand," or Atacamite, from its being 

 obtained from the Atacama Desert, between 

 Chili and Peru, is produced artificially by 

 pounding the crystallized and laminar va- 

 rieties for the purpose of using it as sand 

 for letters (Arsenillo), instead of blotting 

 paper. 



Atacamite is distinguished from Mala- 

 chite by its solubility in nitric acid Avithout 

 effervescence ; the colour it communicates 

 to flame, and the rapidity with which it 

 turns ammonia blue. It differs from arse- 

 niates of copper by not exhaling arsenical 

 fumes BB. 



Brit. Mus., Case 59. 



M. P. G. Principal Floor, Wall -case 16. 



Atelesite. The name given by Breit- 

 haupt to small oblique crystals containing 

 bismuth. 



Athereastite. An altered Scapolite, 

 which it resembles both in form and ap- 

 pearance. Colour green and opaque. 



Locality. The mines of Arendal, in Nor- 

 way. 



AVANTURINE. 31 



Atlaseez. See Malachite. 

 Atrajienstein. See Misy. 



AvANTURINE, AvANTURINO-QUARTZ, Or 



Aventurine. a vitreous variety of Quartz, 

 generally translucent, and of a grey, green, 

 brown, or reddish -brown colour, and con- 

 taining minute yellow spangles. These are 

 most frequently produced by scales of Mica, 

 but sometimes, according to Gahn, by me- 

 tallic copper crystallized in the form of flat 

 segments of a regular octahedron. Aven- 

 turine was formerly found on the north 

 shores of the White Sea ; it is now found 

 tolerably abundantly in Silesia, Bohemia, 

 France, Cape de Gata in Spain, India, but 

 chiefly in the neighbourhood of Kkater- 

 inenburg in Siberia. It is used for ring- 

 stones, shirt-studs, ear-rings, snuff-boxes, 

 and other ornamental articles of a similar 

 kind. By far the finest specimen of the 

 Siberian variety in this country is a highly 

 polished vase, four feet high and six feet in 

 circumference, which, with its pedestal of 

 polished grey porphyry, was presented to 

 Sir Roderick I. Murchison as " the explorer 

 of the geology of Eussia" by the late 

 Emperor Nicholas I. The prevailing tint 

 of this magnificent work of art is French- 

 white or pearl-grey, clouded with delicate 

 rose-coloured tints, and it is equall}^ re- 

 markable for the beauty of the material, 

 and the elegance of its form, as for its 

 excessive rarity ; the difiiculty of procuring 

 a stone of such large dimensions, and of 

 polishing so hard a substance being so great, 

 that only one other similar vase (presented 

 to the late Baron Humboldt, and now in 

 the Royal Museum, Berlin), has been made. 

 The materials of the base and pedestal were 

 obtained in the Kourgon mountains in the 

 province of Tomsk, and were cut and po- 

 lished in Siberia. According to Fremy & 

 Clemandole, beautiful specimens of artificial 

 Aventurine may be obtained by heating 

 together for twelve hours a mixture of 300 

 parts of pounded glass, 40 of protoxide of 

 copper, and 80 of oxide of iron, and after- 

 wards allowing the mixture to cool very 

 slowly. In fact the name for the natural 

 substance has been borrowed from that of 

 the artificial gold-spangled glass, which in 

 its turn, originated in the circumstance of a 

 workman having accidentally (par aventure) 

 let fiill some brass filings into a pot of 

 melted glass, which he thereupon called 

 Aventurine ; and mineralogists subsequently 

 adopted the term, and applied it to the 

 natural substance, an imitation of which 

 had been thus obtained by accident. 

 Brit. Mus., Case 21. 



