GKANITK 



GRANT 



363 



that of the felspar. All varieties <.f texture are 

 met with among granites, from very fine-grained 

 up td coarseU <i\>talliiie rocks, in which the 

 component crystals may he several inchcH in 

 diameter. The coarser-grained kinds are called 

 />( unit id: In the variety known ax graphic 

 fjrnnite the quartz in crystal Used in the ortho- 

 clase, forming alternate zigzag-shaped lamina-, 

 which, mi ,-i <-m fracture, present the appear- 

 ance of Ildircw writing. The accessory minerals, 

 such as beryl, topuz, tourmaline, garnet, sphene, 

 See., are met with chiefly in irregular cavities, and 

 in such cavities very fine crystals of the essential 

 minerals often occur. Scattered through the body 

 of the rock, however, accessory minerals are not 

 uncommon, especially apatite ami sphcne, and less 

 frequently zircon these three minerals occurring 

 as inclusions in the essential minerals. The rela- 

 tive proportion of mica, felspar, and quart/ 

 varies ; m many granites felspar forms more 

 than half of the milk of the rock quartz coming 

 next, and mica last. In other granites there is 

 extremely little quartz, while mica is more 

 plentiful. Sometimes the rock is rendered por- 

 phyritic hy the appearance of large crystals of 

 ortlioclase, embedded in a granitoid or finely- 

 crystalline ground-mass. It Is generally the 

 felspar which gives the prevalent colour to a 

 granite the rock being red or gray according as 

 flash-coloured or white felspar predominates. Very 

 often dark patches and nodules occur in granite. 

 Sometimes these are fragments of foreign rocks 

 more or less altered; at other times they are com- 

 posed of the same minerals as the granite itself, 

 but in different proportions mica often predomi- 

 nating. Veins of similar composition are also 

 found ramifying through granite. These and the 

 patches together are supposed to be ' the result of 

 differentiation accompanying the crystallisation of 

 the original magma ' the dark portions being more 

 basic in composition than the rock in which they 

 occur. Most granites are traversed by lighter- 

 coloured veins some of which are finer grained 

 and others coarser than the rock in which they 

 appear. The origin of these veins is uncertain. 

 They would appear to be of contemporaneous 

 origin with the granite, and to have sometimes 

 formed in rents of the original pasty magma, pos- 

 sibly by segregation of the minerals from the sur- 

 rounding mass. The fine-grained veins, on the 

 other hand, were probably injected before the 

 granite had become quite consolidated. It seems 

 certain at least that the rock of the veins and the 

 granite itself originally formed portions of one 

 and the same molten mass. 



Amongst varieties of granite may be mentioned 

 linrnhlendic granite, in which hornblende is added 

 to the other constituents. When this is the case, 

 mica is only sparingly present. When schorl 

 (black tourmaline) replaces mica, we have schorl- 

 aceous granite. Greiscn is a granular aggregate of 

 quartz and mica. Aplite is a fine-grained aggre- 

 gate of quartz and orthoclase, with sometimes a 

 little mica. These three last-mentioned varieties 

 are met with chiefly in veins proceeding from 

 masses of ordinary granite. 



Granite usually occurs in great losses or 

 amorphous masses and frequently forms the 

 nuclei of mountain -chains. Its petrograpliiral 

 characters and behaviour in the field prove it to 

 be of igneous origin, at all events in the great 

 majority of cases, and to have consolidated at con- 

 siderable depths in the earth's crust. Hence it 

 lielongs to the Plutonic class of igneous rm-k-. 

 Some writers have held that certain granites are 

 of metamorphic origin, but the appearances which 

 -.in to support this view have of recent years 

 received another interpretation. And although, 

 231 



in the present state of our knowledge, it cannot be 

 asserted that no granite in of metamorphic origin, 

 yet it would appear that granites of dcinonxtrahlv 

 metamorphic origin have not yet been discovered. 

 Those which are -ii|.|io-ed to lie of such origin 

 are intimately associated with crystalline schist*, 

 which themselves are Ix-lievcd to. lie the result of 

 metamorphic changes. At one time granite WOK 

 looked upon an the oldest tit primitive rocks, but 

 it is now Known to be of various agw. ItM presence 

 at the surface is due of course to denudation, which 

 has removed the great manses of rock that origin- 

 ally covered it. 



The more durable kinds of granite are largely used 

 as building materials in bridges ami engineering- 

 works, and also in public buildings and dwellings. 

 The difficulty of working it makes it expensive, 

 but this is counterbalanced by its great durability. 

 It cannot be cut, like the majority of building- 

 stones, with saws, but is worked first with large 

 hammers, and then with pointed chisels. The 

 success with which the Egyptians operated upon 

 this refractory stone is very extraordinary. They 

 worked and polished it in a way that we cannot 

 excel, if, indeed, we can come up to it, with all the 

 appliances of modern science ; and not content with 

 polishing, they covered some of the blocks with the 

 most delicate and sharply-cut hieroglyphics ! 



The granites best known in the British Islands 

 for ornamental purposes are the gray Aberdeen 

 granite and the reddish-coloured Peterhead granite. 

 Of this last-mentioned variety handsome polished 

 columns for public halls have leen constructed. 

 On the Continent granite has been quarried for 

 similar purposes in several countries : as near 

 Baveno in Italy, and in the islands of Sardinia and 

 Elba ; in Normandy and Brittany : in southern 

 Sweden, Finland, the Tyrol, Switzerland, &c. In 

 North America granites are worked at a number 

 of places, as in Maine, New Hampshire, Massa- 

 chusetts, Connecticut, New York, Michigan, and 

 California, and at various places in the Canadian 

 province of Quel>ec. The rock would probably be 

 more abundantly used than it is, were it not for 

 the fact that in many cases it occurs at elevations 

 and in districts more or less difficult of access. 



The soil produced by the weathering of granitic 

 rocks should be fertile, as their component in- 

 gredients yield the necessary elements. But in 

 hilly districts, where granite is chiefly developed, 

 the fine clay which results from the decomposition 

 of the felspar is washed away, so that only the 

 quartz sand is left on the slopes forming a thin, 

 ungrateful soil. In the hollows and flats whither 

 the clay is transported we find generally a cold, 

 stiff, and wet subsoil, which is only worked with 

 difficulty. In low-lying granitic tracts, especially 

 under genial climatic conditions, the soil whicli 

 results from the weathering of granite is sometimes 

 very fertile. See Geo. F. Harris, Granite and the 

 Granite Industries ( 1888). 



Gran Sasso d' Italia ( 'Great Rock of Italy'), 

 also called MONTE CORNO, from the resemblance 

 to a horn which it presents on the east, is situated 

 on the liorders of the Abruz/i, letween Teramo and 

 Aqiiila. It is the highest summit of the Apen- 

 nines, having an elevation of 9574 feet. 



Granson, or GRANDSON, an ancient town in 

 Swit/.erland, on the Lake of Neuchatel, 21 miles 

 SW. of Neuchatel: pop. 17(>2. Here in 1476 the 

 Swiss defeated Charles the Bold (q.v. ). 



Grant, in English law, the conveyance of pro- 

 perty by deed. Movables are granted when they 

 are 'comprised in a bill of sale or deed of gift. 

 Incorporeal hereditaments, and interests in land 

 not involving actual possession, were also said to 

 lie in grant ; but a freehold in possession could 



