MINERALOGY. 57 
until Chladni, in 1794, took up the question, and soon accumulated such a 
mass of proof as to satisfy the most sceptical. Meteoric iron generally 
occurs in jagged and roughly-vesiculated fragments (pl. 33, fig. 1). It is 
not perfectly pure, generally containing a slight quantity of some other 
metals, of which nickel has been found in all undoubted meteorites. In the 
meteoric iron of Ellbogen were found, in one hundred parts: iron, 88.231 ; 
nickel, 8.715; cobalt, 0.762; and manganese, 0.249. Meteoric iron has a 
crystalline texture by which it is recognisable. By sawing off a corner and 
polishing it, the application of dilute nitric acid will develope triangular and 
lozenge-shaped figures, mostly of 60—120° inclination, the sides all bounded 
by double lines. These figures, shown in fig. '7, are known as the Weid- 
mannstedtian figures, from their discoverer. The iron of commerce is 
obtained in furnaces by reduction from oxydes or carbonates. 
2. Native Silver. 
Silver frequently occurs native in silver mines, and also alloyed with 
other metals or simple bodies; in the form of sulphuret of silver it is very 
abundant. Native silver occurs crystallized (pl. 33, fig. 9), exhibiting the 
forms of the regular system, as the cube, the rhombic dodecahedron 
( fig. 30), the pyramidal cube (fig. 40), and the octahedron (fig. 42); or 
else it is found in filiform (jig. 16), or in arborescent (jig. 12) shapes, 
sometimes in coarse masses, in plates, &c. Native silver, like most native 
metals, is not perfectly pure, containing a variable amount of gold, copper, 
antimony, and arsenic, without any change being produced in its external 
or crystalline form. Its color alone is affected in these mixtures, varying 
from silver-white to brassy-yellow. Silver is very ductile and malleable, 
and difficult of fusion. It occurs mostly in veins, more seldom in beds in 
primitive rocks, granite, porphyry, and gneiss; in transition and stratified 
rocks, accompanied by barytes, hornstone, or calcareous spar. The 
principal localities of native silver are in Saxony, Bohemia, Hungary, the 
Hartz, Norway, Siberia, Mexico, &c. It occurs associated with the native 
copper of Lake Superior. The silver of commerce is obtained partly from 
native silver, partly from the sulphuret, or from combinations of the 
sulphuret with other sulphurets, such as antimony and arsenic. It is found 
in especial quantity in reducing lead from galena (sulphuret of lead). It is 
obtained by reduction, by amalgamation, or by cupellation. 
3. Native Gold. 
Gold rarely occurs in any other form than native. In this state, like 
silver, it is alloyed at times with other metals, in variable, not definite 
proportions. The principal alloys are with silver, copper, iron, platinum, 
iridium, and palladium, the crystalline form not being necessarily changed 
thereby. The color of these alloys varies from golden-yellow to silvery- 
white. It has a specific gravity of from twelve to twenty, is rather soft, 
and exceedingly extensible. The crystals of native gold belong to the 
regular system; the most common forms are shown in pl. 33, figs. 32, 33, 
35, 36,40, 41, 42,43,44,45. It also occurs in various uncrystallized forms ; 
in arborescent ramifications, as in fig. 14; also in filiform and reticulated 
masses, in coarse lumps, scales, and grains. Its original locality is in veins 
487 
