322 KOCK SOAP, 



and in the preservation of meat, butter, &c. 

 Formerly it was used more than is the case 

 now, as a glaze for earthenware and pot- 

 tery. The other principal uses to whicn it 

 is applied are as a manure, in soap-making, 

 as a flux in metallurgical operations, and in 

 the manufacture of chlorine, carbonate of 

 soda, muriate of ammonia, &c. The salt 

 for commercial purposes is obtained : 1st. By 

 mechanical extraction from salt-beds ; 2nd. 

 By dissolving impure Rock-Salt in fresh- 

 water, in the water of saltsprings, or in 

 sea-water, and then decanting and evapo- 

 rating ; 3rd. By boiling down the liquid from 

 the salt-springs, after it has become con- 

 centrated either by exposure to the air in 

 graduating works, or, more rarely, by partial 

 congelation of the water; 4th. By the eva- 

 poration of sea-water either in the sun or 

 by artificial heat. 



Brit. Mus., Case 59. 



31. P. G. Horse-shoe Case, Nos. 188 

 to 196. Wall-case 38. Upper Gallery, 

 Wall-case 40. 



Rock. Soap, Jameson. Resembles Bole. 

 Colour pitch- or brownish-black. Opaque. 

 Dull. Feels slightly greasy. Streak shin- 

 ing and resinous. Sectile. Fracture fine, 

 earthy, or conchoidal. Does not soil, but 

 writes as well or better than drawing slate. 

 Adhei:es strongly to the tongue. Falls to 

 pieces in water. H. 1 to 2. S.G. 2*66 to 2*7. 



Comp. Nearly Al Si2 + 6H. 



Analysis, from Plombieres, bv Berthier ; 

 Silica . . . " . 44-0 



Alumina .... 22-0 

 Magnesia . . , .2-0 

 Sand ..... 6-0 

 Water . . . = . 25-0 



99-0 



Localities. Isle of Skye, in basalt, and in 

 the trap rocks of Antrim, in nodules of a 

 greenish-grey or brown colour (Creg). 

 Artern, in Thuringia. Cassel. Bilin, in 

 Bohemia. Olkuce, in Poland. Wehrau, in 

 Upper Saxony. 



Rock Soap is used for washing cloth, and 

 for artists' crayons. 



Rociv Wood, Jameson. The name given to 

 a ligniform variety of Asbestos, in which the 

 fibres occur in long, curved, parallel masses, 

 with a closer texture than in Rock Leather 

 or Rock Cork. Its colour is various shades 

 of wood-brown. It is chiefly found at 

 Sterzing, in the Tvrol. 



Brit. Mus., Case 34. 



RoETHEL, Werner. See Reddle. 



IioH>vAND. Oue of the names given to 



ROSE QUARTZ. 

 Ankerite by the Styrian miners, who value 

 it both as a flux and as an ore of iron. 



ROMANZOVITE, Or RoMANZOWITE, Nor- 



denskiold. A brown or brownish - black 

 varietj' of Lime-Garnet, occurring in com- 

 pact or crystalline plates, with a greasy 

 lustre and a resinous fracture. Streak pale 

 yellow. 



Analysis, by Nordenskiold : 



Silica 41-24 



Alumina .... 24-08 

 Peroxide of iron . . . 7-02 

 Protoxide of manganese and 

 magnesia .... 0*92 



Lime 24-76 



Ignition and loss . . . 1*98 



100-00 



BB fuses without ebullition. 



Locality. Kiiuito, in Finland. 



Name. After Count Romanzow. 



Brit. Mus., Case 36. 



3L P. G. Horse-shoe Case, No. 899. 



RoMElNE, Damour, Dana, Dufrtnoy. 

 RoMEiTE, Nicol. Pyramidal. Occurs in 

 groups of minute octahedrons, or inclosed 

 in the massive mineral. Colour hyacinth- 

 red or honey-yellow. H. 5. 



Comp. R3, Sb or Ca Sb (Rammelsberg), 



Analysis, by Damour : 



Antimonious acid . . 79-31 



Lime 16-67 



Protoxide of manganese . 2-60 

 Protoxide of iron . . .1-20 

 Silica 0-64 



100-42 



BB fuses to a blackish slag ; with borax 

 affords a colourless glass in the inner flame, 

 and a violet glass in the outer flame. 



Insoluble in acids. 



Locality. The manganese mines of St. 

 Marcel, in Piedmont. 



Name. After Rome de Lisle, the cele- 

 brated crystallographer and mineralogist. 



Brit. Mus., Case 38. 



Rose Quahtz. A transparent, or nearly 

 transparent, variety of Quartz, of a rose- 

 red (u- pink colour. It usually occurs mas- 

 sive, and often much cr.icked. S.G. 2-659 ; 

 after being heated 2-6578. Lustre vitreous, 

 sometimes slightly' greasy. Fuchs attributed 

 the colour to oxide of Titanium, from the 

 presence of 1 to 1-5 per cent, in specimens 

 from Rabenstein, near Bodenmais. Berthier 

 attributes the colour to organic matter. Pro- 

 bably it is produced by manganese, the 

 colour resembling that of Manganese Spar. 



Localities. — Scotch. On the hills of Kil- 



