30 ASTERIA. 



tion of water, and possesses the property of 

 plasticity, which it gradually loses on long 

 exposure to the sun and atmosphere. 



3. Asphaltic Oil, occurring associated 

 and diluted with water, but when concen- 

 trated it apyjears as a dense black fluid, 

 with a powerful bituminous odour. If col- 

 lected in an open vessel, the more volatile 

 part evaporates after a few months, leaving 

 a solid black substance of similar appear- 

 ance, and with properties analogous to those 

 of Asphaltum Glance. 



Asphaltum is also found near Matlock, 

 and in the Odin mine, near Castleton, in 

 Derbyshire, and occasionally in the Free- 

 stone" Quarries at Binney, near Edinburgh, 

 where it is so abundant, that the work- 

 men make candles of it. In Cuba it is 

 very extensively diffused {Chapapote). It 

 is also found along the margin of the Mag- 

 dalena Valley, in New Grenada, Coxitam- 

 bo, in Peru, "of great purity, with a high 

 lustre, and a perfect conohoidal fracture. 

 In Texas, within 100 miles of Houston, 

 there is a small lake about a quarter of a 

 mile in circumference, filled with Bitumen 

 or Asphaltum. In France at Aniches (De- 

 partment du Nord); near Alcobaca, in 

 Portugal ; Avlona in Albania ; Mount Leba- 

 non ; Arabia ; Persia ; in the countries on 

 the borders of the Tigris ; and the Lower 

 Euphrates; and in Koordistan ; Birmah; 

 Ava; Pegu; &c. 



Asphaltum was employed by the an- 

 cient Egyptians in the process of em- 

 balming the dead, either alone, or in combi- 

 nation with other substances. The ancients 

 also used it as an ingredient in mortar, and 

 the walls of Babylon are said to have been 

 built of a mortar of this kind. The people 

 of Arabia still use a solution of it, in oil, to 

 besmear their horse-harness, to preserve it 

 from insects, and in Albania it is used for 

 paying the bottoms of ships. Two ship- 

 loads of Asphalt were sent to this country 

 from the Pitch Lake of Trinidad, by Admi- 

 ral Cochrane; but it was found that the 

 cost of the oil necessary to render it fit for 

 use exceeded the price of pitch in England, 

 and the project was therefore abandoned. 

 Asphalt is used for lining cisterns, and for 

 pavements. It is also a constituent of 

 Japan varnish. 



Brit Mus., Case 60. 



M. P. G. A 28 in Hall, large mass from 

 the Pitch-Lake, Trinidad. Horse-shoe 

 Case, Nos. Ill to 116. 



AsTERiA. The name used by Pliny to de- 

 note the asteriated crystals of Sapphire, or 



ATACAMITE. 



is an opalescent variety of Sapphire, which, 

 when cut en cabochon, displays a silvery star 

 with six rays. It is semi transparent, and 

 has often a reddish-purple tinge. The sum- 

 mits of the primary rhombohedron are 

 replaced by secondary planes, that present 

 a varying chatoyant lustre. If these cry- 

 stals are cut en cabochon, or in the form 

 of an ellipse, taking care that the summit 

 of the ellipse shall be situated exactly over 

 the point corresponding with the summit of 

 the rhombohedron, there will be produced 

 the appearance of a star with six rays, from 

 which, when held in the sunshine, a bright 

 yellowish-white light streams forth in beau- 

 tiful contrast to the rich purplish blue of 

 the other parts of the stone. The flatter 

 the ellipse the more varying is the lustre 

 displayed over the surface of the stone ; as 

 on the other hand, with a high ellipse it is 

 condensed on a single spot."— (Mawe). 



" The jewellers appraise the value of the 

 Ayn~ul-hireh according to the number or 

 perfection of the threads {zandr) visible in 

 it, which should give the stone, when 

 turned about, the appearance of a drop of 

 floating water. This description accords 

 with the quartz Cat's-eye rather than with 

 the asteria ; but there is some difficulty in 

 reconciling the uncertainties regarding this 

 mineral. The Ayn-ul-hireh, probably com- 

 prises both of the above minerals ; in the 

 same manner as the turmali apparently em- 

 braces both the tourmaline and zircon fami- 

 lies."— Prmsep: ''Oriental Account of the 

 Precious Minerals.''^ 



AsTRAKANiTE, Rose. A mineral occurring 

 in whitish, transparent or translucent, im 

 perfect prismatic crvstals, in the salt lakes 

 east of the mouth of the Volga. S.G. 2-251. 



Comp. Mg. S + Na S + 4 H, or sulphate of 

 magnesia 35-9, sulphate of soda 42 '5, 

 water 21-6 = 100. ^ ^ . m 



ASTKAPHYA LITE, from kffriot.^^, a flask oj 



lightning. See Fulgurite. 



Asphaltum Glakce. See Asphalt. 



Atacamite, Dana, Jameson, Nicol. Rhom- 

 bic; usually occurs in minute rectangular 

 octahedrons, or in modified rectangular 



Fig. 31. 



note uie asLcruii«uciv=.a.. .. ^at^p...... ... , prisms ; also massive lamellar. Colour ya 



those displaying diverging rays of light. It rious shades of bright green, rather darke 



