GOKUMITE. 



blood-red by transmitted light. Lustre 

 adamantine. Streak brownish-vellow. Brit- 

 tle. H. 5 to 5-5. S.G. 4 to 4-4. 



Fig. 214. 



^^^i^ 



Fig. 215. 



Comp. Hydrated peroxide of iron, or 



Fe H = peroxide of iron 89-89, water 10-11 



= 100. 

 Analysis, from Eisenfeld in Nassau, bv 



V. Kobell; 



Peroxide of iron . . . 86-35 



* Silica 0-85 



Oxide of copper . . . 0-91 



Lime trace 



Peroxide of manganese . 0*51 

 Water 11-38 



100-00 



BB behaves like Limonite. 



Localities. — English. The finest and most 

 perfect crystals hitherto found occur in 

 Quartz at Restormel iron-mine near Lost- 

 ■\vithiel in Cornwall ; it is also met with in 

 the same county, at Botallack, near St. Just, 

 and at Tincroft, Illogan, in fibro-crystalline 

 specimens ; at Carn Brea and Huel Beau- 

 champ near Redruth, in translucent plates 

 of a hyacinth-red colour. In Gloucester- 

 shire it is found in diverging tufts of needle- 

 shaped crystals in the interior of geodes ; 

 in Somersetshire at the Providence iron- 

 mines near Bristol, associated with very 

 fine amethystine Quartz. — Scotch. Gou- 

 rock in Renfrewshire, and at Burn of the 

 Sail, Hoy, in the Orkneys. — Foreign. The 

 principal foreign localities are Eiserfeld in 

 Siegen, Prussia; Oberkirchen in Wester- 

 wald; Zwickau in Saxony ; Przibram, &c. 



Name. After the German poet and 

 mineralogist, Goethe. 



Brit. Mus., Case 16. 



3I.P.G. Principal floor, Wall-cases, 49, 

 27 and 43 (British). 



For varieties of Goethite, see Lepido- 



KROKITE, OnEGITE, PrZIBRAMITE, RuBIN- 



GLiMJiER, Sammetblende, and Stilpno- 



SIDKRITE. 



GoKUMiTE. A variety of Idocrase from 

 Gokum. 



Gold. Primary form the octahedron. 

 Often occurs in grains or scales {Grajios), 

 and in rolled masses (Pepitas, Nuggets) 

 in alluvium and gravel. The crystals, 



GOLD. 157 



usually small and imperfect, are sometimes 

 cubes or octahedrons (frequently with trun- 

 cated edges or angles) ; dodecahedrons 

 with rhombic faces, and solids with twenty- 

 four trapezohedral faces. Colour and streak 

 various shades of gold- yellow, sometimes 

 inclining to silver -white. Lustre metallic. 

 Opaque. Very ductile, flexible, and malle- 

 able. Fracture hacklv, affording no trace 

 of cleavage. H. 2-5 to'3. S.G. 15-6 to 19'5. 



fig- 216. Fig. 217. 



Gold is almost always found native, but 

 seldom perfectly pure, being alloved with 

 minute quantities of other metals, which 

 sometimes considerably aflPect its colour. 

 Sometimes it occurs in combination with 

 silver, constituting Electrum ; with tellu- 

 rium, in Native Tellurium ; with silver and 

 tellurium, in Graphic and Yellow Tellurium ; 

 and with lead and tellurium, in Foliated 

 Tellurium. A native amalgam of gold has 

 been found in California, especially near 

 Mariposa and in Columbia, and an alloy of 

 gold and bismuth in Rutherford Countj-, 

 North America. It sometimes occurs in 

 small quantities in metallic sulphides, as in 

 Galena, Iron Pyrites, and Copper Pyrites, 

 and is occasionally alloyed with Palladium 

 (see Porpesite) and Rhodium. 



Gold being one of the most widely difi'used 

 of minerals, a few only of the principal loca- 

 lities can be given here. It was probablv 

 discovered by the aboriginal inhabitants of 

 the British Islands at a very earlv period, 

 long prior to their invasion by the "Romans, 

 most of the fibulse, torques, and other gold 

 ornaments found in the barrows of this 

 country and in the peat bogs of Ireland 

 having been obtained from native sources. 

 At a subsequent period, the Romans, always 

 anxious to avail themselves of the natural 

 resources of their colonies, carried on opera- 

 tions in a more systematic manner, and are 

 supposed to have had works at North 

 Molton in Devonshire, as well as at Gogofau, 

 near Caio, in Caermarthenshire,in the neigh- 

 bourhood of a place now called Pumpsant* 

 Since that time various attem.pts have been 



* See " Note on the Gogofau, or Ogofau, Mine 

 by Wanngton W. Smyth, M.A.," in Memoirs of 

 the Geological Survey of Great Britain, vol i 

 p. 480. 



