GRAMMATITE. 

 Protoxide of manganese . 0-67 

 Magnesia .... 0*7o 



Lime 0-56 



Potash . . . . .1-14 

 Water 23-36 



100-00 



In a tube becomes dull brown, giving off 

 much water. 



BB behaves like Pinguite ; becomes mag- 

 netic. 



Completely decomposes in acids, but with 

 difficulty. 



Locality. Menzenberg, in the Siebenge- 

 birge. 



Name. From gramen, grass, because of its 

 green colour. 



Gramimatite (from r^^.t^A'-'i, a line). A 

 variety of Tremolite, from Aker in Sweden. 



Grammite. See Wollastonite. 



Granat, Werner, Molis, Haidinger, Haus- 

 mann. See Garnet. 



Granatit, Werner. Staurotide. See 

 Grenatite. 



Granular Corundum. See Emery. 



Granular Epidote, Phillips. See 



SCORZA. 



Granular Hea-vy Spar. Tha name 

 given to fine-grained varieties of Barytes. 

 It is found massive, in beds accompanying 

 Galena, at Peggau, in Styria; also in the 

 mining district of Fre^'berg, in Saxony, 

 and at Schlangenberg, in Siberia, where it 

 is associated with Copper-Green (Chryso- 

 colla), and Native Copper. It may be dis- 

 tinguished from limestone, to which it bears 

 a striking resemblance, in possessing less 

 lustre and hardness, and in being much 

 heavier. 



Granular Iron Ore, Kirwan. See 

 Bohnerz, 



Granular Quartz. Massive quartz-rock 

 of a granular texture. Its colours are vari- 

 ous, but always dull. 



Graphic Gold, Graphic Tellurium, 

 Phillips. See Sylvanite. 



The name bears reference to the particular 

 appearance produced by the aggregation of 

 the capillary crystals, which are frequently 

 disposed in rows more or less resembling 

 graphic delineations. 



Graphite, Dana, Greg §- Lettsom, Jame- 

 son. Hexagonal, primary form a regular 

 six-sided prism. Occurs crystallized in fiat 

 six-sided tables, having the basal planes 

 striated parallel to the alternate edges. 

 Commonly in kidney-shaped concretions, 

 or in imbedded, foliated, or granular masses. 

 Cfolour iron- or dark steel-grey. Lustre me- 



GRAPHITE. 161 



tallic. Opaque. Soils paper. Feels greasy. 

 Sectile. Very flexible in thin laming. 

 Streak black and shining. Not very brittle. 

 Fracture granular and uneven. H. 1 to 2. 

 S.G. 2-089. 



Comp. C or carbon, with a variable 

 quantity of iron, &c. mixed with it. 



It always contains a small quantity of 

 iron, often amounting to 5 per cent., but 

 some specimens (as in those from Barreros 

 in Brazil), scarcely contain a trace. The 

 iron is, therefore, to be considered merely 

 as an accidental admixture, and not as ak 

 essential constituent of tbe mineral. 



Graphite, from Wunsiedel in Bavaria, 

 yields only O'oo per cent, of ash, consisting of 

 potash, silica, and oxide of iron : it is there- 

 fore nearly pure carbon.— ( Fuchs.) Graphite, 

 from Germany (S.G. 2-273), contains 95-12 

 per cent, of carbon, and 6-73 per cent, of 

 ash, chiefly consisting of grains of Quartz. — 

 (Begnault.) Graphite, from Bustletown, in 

 Pennsylvania, contains 954 per cent, of 

 carbon, 0-6 of water, 2-6 of sihca and alu- 

 mina, and 1-4 of the oxides of iron and man- 

 ganese. — ( Vanuxem.) The purest Graphite, 

 from Ceylon, yields only 1*2 per cent, of ash ; 

 other varieties 6 to 37-2 per cent., consisting of 

 oxide of iron and earthy matters. Graphite, 

 from the Himalaya Mountains, contains 71-6 

 per cent, of carbon, 5-0 of iron, 15 of silica, 

 and 8-4 of alumina, &c. — {J. Prinsep.) 



Analysis (a) from Borrowdale, (6) from 

 Spain, by Schrader : 



(a) (b) 



Carbon . . . 85-25 88-7 

 Protoxide of iron . 5-80 7-1 

 Silica . . . 3-50 1-5 

 Alumina . . . 2-30 1-2 

 Oxide of copper . . 0-00 1-0 

 Oxide of titanium . 3-15 1-5 



100-00 100-00 



At a high temperatiu-e, burns without 

 flame or smoke, leaving usually some red 

 oxide of iron. 



BB becomes yellow or brown after long 

 continued heat, but is infusible both alone 

 and with reagents. 



Unaltered b}^ acids, which only affect the 

 iron or other impurities. 



Localities. — British. Graphite is found in 

 nests of trap, occurring in clay-slate at Bor- 

 rowdale, in Cumberland * ; at a mine near 



* " The Plumbago, from Borrowdale, in Cum- 

 berland, has long been celebrated for its fine 

 quality ; it is found in detached pieces, called, ac- 

 cording to their size, sops or bellies, so that the 

 supply is very irregular, the miners being fie- 

 M 



