J 
394 General Notes. LApril, 
rather an extension of the ordinary works on mineralogy. Although 
quite elementary, it will prove very valuable to those commencing 
work in microscopical mineralogy, to whom the vast amount of 
material contained in the larger manuals is often discouraging. 
CROCIDOLITE FROM THE CAPE oF Goop Hopr.—Considerable 
which jewelers generally designate as crocidolite. In its struc- 
ture it much resembles the well-known “catseye,” and when 
properly cut it can scarcely be distinguished from this except by 
its color, a fact which frequently causes it to be called “tiger’s 
.” The true crocidolite is an asbestiform hornblende, possess- 
ing a blue color, like its more compact equivalent glaucophane. 
Among other localities it occurs abundantly near the Orange 
river in South Africa, from which place specimens were analyzed 
by Klaproth? as early as 1815, and again by Hausmann and Stro- 
meyer’ in 1831. The latter authors gave it the name crocidolite 
in allusion to its fibrous structure («poxés, a woof). The occur- 
rence of this mineral in Africa has been described by Cohen? and 
Stow." The former says that a range of mountains extends in 
N. N. E. direction from the Orange river through the province of 
West Griqualand, the central part of which is known as the 
Asbestos mountains. Here the crocidolite occurs in veins from 
one to six inches in width, together with vast quantities of jasper 
and other forms of silica. Sometimes the crocidolite is pure and 
is then blue in color, soft, and easily separable into the finest 
fibers; more often, however, it is more or less decomposed and 
toa greater or less extent replaced by quartz. It is upon this 
alteration and replacement that the commercial value of the min- 
eral depends. The yellowest specimens are most changed and 
owe their color to the almost complete oxydation of the iron. 
WibeP’ studied the mineral in 1873 and concluded that it was a 
complete pseudomorph of quartz after crocidolite, only the iron 
of the original mineral being left in the form of gothite. Renard 
and Klement® have recently contributed an exhaustive paper on 
the subject.’ Analysis of the yellowest variety gave: 
PROG Mee 6 Rta ole Oo oO 
85.05 4.94 - 0.66 0.44 8.26 0.76 
Total 100.11 
i Spn Abhandlungen gemischten Inhalts, 1815, pp. 233-242. Beiträge, VI, 
, 1815. 
* Gétting’scher gehl. Anzeiger, 11, 1831, p. 1887. 
$ Neues Jahrbuch fiir Min., etc., airs “a Pa 5 
ee 3 jaana es er ia . 622, 
o a een Ie in. etc., 1873, p. 367. (H. Fischer proved the same was 
< the case for many varieties of Ete ha EA ( a 
ermak Min. Mittheilungen, 1373, P. 
Er 
o Fun, d. Acad. Roy. d. Sciences de Belgique (3), vitt, 1884, 530-550. 
