50 
NATURAL HISTORY. 
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Case 3. Native gold, subdivided into pure and alloyed gold; the 
former chiefly massive, in detached crystals and as grains (from the al¬ 
luvial deposits of Guinea, Sumatra, Bengal, Brazil, Leadhills in Scot¬ 
land, &c.), and in brown iron-stone, in quartz, with needle-ore, &c., 
from Siberia; the alloyed gold (principally from Transylvania) crystal¬ 
lized in minute cubes and octahedrons variously aggregated, in reticular 
plates, &c. With these are placed a few specimens of the native alloys 
known by the names of electrum: the electrum of Smeof or Schlan- 
genberg, in Sioeria, contains one-third of silver. 
In this Table Case begin (continued to Case 12) the electro-negative 
metallic substances called metalloids, and their non-oxidized combina¬ 
tions. — Tellurium and tellurets . the scarce native tellurium, which element 
(like sulphur and selenium ) has the property of mineralizingseveral metals, 
combining with them as electro-negative substance, viz.—with bismuth 
(a compound formerly called molybdena-silver) from Bastnaes : to which 
also belongs the tetradymite; — with silver, from the Altai, Siberia; -with 
lead (foliated tellurium, or nagyag ore);—with silver and lead (white 
and partly yellow tellurium) ;—with silver and gold (graphic tellurium or 
schrift-ertz of authors), all from Transylvania, where they occur in veins 
traversing greywacke and porphyry .—Native antimony from Dauphiny 
and the scarce antimonial silver or stibiuret of silver from the Hartz, &e. 
Case 4. Native arsenic (formerly called testaceous cobalt and scher- 
ben-cobalt), in reniform and botryoidal shapes, from Andreasberg, &c.; 
and its chemical combinations (arseniurets )—with nickel (a variety of 
which is commonly called red or copper-nickel on account of its 
colour) ;—with cobalt, (arsenical cobalt of authors partly,) comprising 
the grey and part of the white cobalt of some mineralogists (ro which 
probably belongs the bismuth- cobalt or kerstenite of some mineralogists). 
The remainder of this Case contains the substances belonging to the 
orders of Carbon and of Selenium. To the former element are referred 
the diamond, anthracite, and graphite; to the latter the selenium 
metals or seleniurets. Among the specimens selected to illustrate the 
crystalline forms of the diamond are:—the primitive regular octahedron; 
the same with solid angles truncated ; with edges truncated, forming the 
passage into the rhomb-dodecahedron; varieties of the latter, giving 
rise to the six-sided prismatic and the tetrahedral forms ; cubes with 
truncated and bevelled edges ; various hemitropic crystals or macles of 
diamonds; an octahedral diamond, attached to alluvial gold; two 
others in a siliceous breccia with cement of hydrous oxide of iron, and 
one in compact brown iron stone, from Brazil; models of large dia¬ 
monds, &c. With these are placed specimens of the alluvial rock in 
which this precious substance occurs in the East Indies and also in Brazil, 
where it is known by the name of cascalhao ;—varieties of anthracite or 
kohlenblende (to which may be referred the Kilkenny coal), from various 
localities, with native silver from Kongsberg, &c. ;—graphite (commonly 
called black-lead), massive (the purest and most compact variety of 
which is that from Cumberland), disseminated in porcelain earth, &c. 
Selenium is found in chemical combination with several metals: 
the seleniurets here deposited are : lead-seleniuret; — copper-lead- 
seleniuret;—mercury-lead-seleniuret;—cobalt-lead-seleniuret, all from 
Tilkerode, Hartz; — copper-seleniuret; — copper-silver-seleniuret 
( eukairite ), both from Strickerum, Sweden ;—to which are added spe¬ 
cimens of sulphur, from the island of Volcano, incrusted and coloured 
