FUCHSITE. 



Brit. Mus., Case 35. 



FuCHSiTE. A variety of Mica, in which a 

 portion of the alumina is replaced by sesqui- 

 oxide of chromium. It is found in compact, 

 ycaly, and likewise regular slaty masses, 

 frequently accompanied by pure Quartz. 

 Colour emerald-green, passing into dull yel- 

 low. Hardness between Gvpsum and Eock 

 Salt. S.G. 2-86. 



Comp. 38(3 K, Si) + 2(3 Na, bi) + 360(^1, 

 Si) + 24(-e-r, 3 Si) + 18(Mg, Si) + 12(Fe, 3 Si> 

 + 9 Ca F (Schaffliautl). 



Analysis, by Schaffdutl : 



Silica .... 



. 47-95 



Alumina 



. 34-45 



Peroxide of iron . 



. rso 



Oxide of chromium 



. 8-95 



Lime .... 



. 0-42 



Potash .... 



. 10-75 



Soda ..... 0-37 

 Magnesia . . . .0-71 

 Fluoric acid .... 0*35 



10075 



BB with soda, swells up and fuses to a 

 3'ellowish-brown globular slag, which, after 

 continued exposure to the flame, acquires a 

 dull green colour, and is slightly affected by 

 the magnet. 



Dissolves slowly in borax, forming a clear 

 globule, which is yellow Avhilehot (from the 

 presence of peroxide of iron), but a fine yel- 

 lowish-green Avhen cold, owing to the pre- 

 sence of chromium. 



Locality. Schwarzenstein, in the Tyrol. 



Name. After Professor Fuchs, of Got- 

 tingen. 



Brit. Mus., Case 32. 



Fulgurites. (From fulgur, lightning.^ 

 Vitrified tubes, produced by the action of 

 lightning on sand. They are found some- 

 times in the sand and sand-hills on the 

 coasts of Cumberland and Lancashire and 

 elsewhere. 



Brit. Mus., Case 21. 



M. P. G. Principal Floor, Wall- case 42. 



Fuller's Earth, Kirwan. Massive. Co- 

 lour usually greenish-brown, or greenish- 

 grey, sometimes blue. It is opaque, soft, 

 dull, with a greasy feel and an earthy frac- 

 ture. Yields to the nail, and aff"ords a shin- 

 ing streak. Scarcely adheres to the tongue. 

 Becomes translucent when placed in water, 

 and falls into a pulpy impalpable powder, 

 without forming a paste with it. S.G. 1-7 

 to 2-4. 



FUSIBLE QUARTZ. 145 



Comp. Earthy hydrous silicate of alu- 

 mina, orAlSi + H; consisting, when pure, 

 of silica 45, alumina 20, water 25 = 100*00. 

 Analysis, from Reigate, by Klaproth : 

 Silica ....'. 5300 

 Alumina .... 10-00 

 Peroxide of iron . . . 9-75 

 Magnesia .... 1-25 

 Lime . . . . . 0-50 



Potash trace 



Muriate of soda . . . 0-10 

 Water 24-00 



98-60 



BB fuses to a porous slag, and ultimately 

 forms a white blebby glass. 



Localities. — English. Fuller's earth is 

 found in several places in the United King- 

 dom ; at Nutfield, near Reigate, and at 

 Bletchingly, in Surrey, in Lower Greensand : 

 Debtling, near Maidstone, in Kent; Tilling- 

 ton and Petworth, in Sussex ; Apsley and 

 Wavendon, near Woburn, in Bedfordshire ; 

 Catsgrove, near Reading, in Berkshire; the 

 Downs, south of Bath, in Somersetshire, at 

 the base of the Great Oolite. — Scotch. Quarry 

 Wood, in Morayshire ; Bridgehouse, in Pee- 

 bles-shire. — Foreign. It is also found at 

 Rosswein, in Upper Saxony; at Rittenau, 

 in Alsace ; Osmundburg, in Sw^eden ; Vahls, 

 near Aix-la-Chapelle; Zwikowetz, in Bo- 

 hemia, &c. &c. 



This substance was formerly used in large 

 quantities by cloth manufacturers for cleans- 

 ing woollen cloth, on accouut of its great 

 capacity for absorbing oil and grease. The 

 operation is called "fulling," hence the 

 name. Fuller'' s Earth, was given to the sub- 

 stance employed. At the present day, how- 

 ever, the consumption of Fuller's Earth has 

 very much fallen off, in consequence of the 

 adoption of other substances for effecting the 

 object. 



Brit. Mus., Case 26. 



FuLLONiTE. See Onegite. 



FuNKiTE. A variety of green Coccolite, 

 found in lamellar limestone at Bodksater, in 

 Gothland. It occurs in rounded grains of a 

 clear olive-green colour, with a glassy lus- 

 tre. H. scratches glass. 



BB fuses with difficulty. 



Fuscite. Crystallized Pyrargillite, from 

 Arendal, in Norway. 



Fusible Quartz, Jameson. See Obsi- 

 dian. 



