OR YCTOGNOSY. 
are fmall, ro ae Ane) ae as in — brown 
matite ;—druft ing minute, prominent, equal cryf- 
it on the palate as in ee :—rough ; pers the eleva- 
tions are minute, and almoft imperceptible, asin quartz: 
{mooth :—fingly ftreaked: cryftals are ftreaked longitu- 
pele as in eS fhorl ; tranfverfely, as in rock-cryttal ; 
diagonally, in aplome ; alternately ftreaked, wheu the 
traniverfe oe eae satay occur on alternate planes, 
c iron pyrite and brown iron-ftone :—doubly ftreaked ; 
ane rmly doubly ead or hkea aan in eal 
sar reticularly or net-fhaped, as in grey c 
The es Luffre.—In ‘this third pace alee caine 
chara er we have to dilin ui 
3 as in ana pitch ftgne, 
copper pyrites ;— gliftening, or weakly fhining, as in grey 
copper ore, porcelain, jafper, and fplincery quartz :—glim 
ch 
b. ind of lultre, which is eith 
The common luftre belongs chiefly to-earthy ftones: and 
falts: it is vitreous or glaffy; as in rcck cryftal, topaz: 
refinous; in pitch-ftone, yello re:—pearly 3 i 
cyanite, zeolite, and felenite:—adamantine; in diamond, 
white lead ore :—femi-metalli ica, hematite 
The — luftre we have in copper pyrites, grey copper 
ore 
IL. nice of the Fradure.— Here, asin the external oie 
three kinds of characters prefent thenfelves, viz the luf 
of — the fracture, and the form of the fra sesh 
re of the fraGture, or the internal rai its 
determination : the fame as that of the external lu 
Gure. (a.) The compad fracture; its ees are 
oarfe or fine fplintery; both of whic 
cbanliton ne, lime-fone and quartz 
—even, as in in galena, Ly -dian ftone, calcedony, epi : 
—conchoidal ; which 1s diftinguifhed, according to the fize, 
into large and 
S 3 
iplintery, either ¢ 
kinds of f 
grained, as in copper pyrites; or fmall- grained, as in copper 
niekel; or fine-grained, as in arfenical pyrites :—earthy ; as 
clay iron-ftone, &c.:—hackly; in which t 
fharp points, which is a to ee 
: ) 
; which js ftraight, as in red hematite; or 
curved, as in black hematite and fibrous rock-falt :—the 
Sat of the fibres, which is promifcuous, as in plumofe 
y3 patallel, as in amianth; or diverging, which 
eee is diltinguifhed into corral as in brown hematite; 
~ es ae as in red hematite and malachite. 
ated fracture, ‘which i is {ubdivided, according 
to the earn of the rays, into uncommonly kroad radiated, 
grey antimony ; paralle 
which eee: is alee ftellular, in _— om or {co 
form, as in grey antimony. 
the rays, we find ase furface either ae as in horn- 
blende, or {mooth n aGinote and antim 
d. The foliated peau, in which are . / determined 
pe 
egard co the afpect of gale 
= fize of the folia:—the degree of perfection . the = 
ccording to which the fra¢ture is fpecular, as in gale 
perfedily foliated; imperfe@tly foliated, as in ne ae flaty, 
as in clay flate; and concealed foliat ted; as in hes crytftal ; 
—the direGtion of the folia, which is ftraight, a in felenite, 
or curved foliated; this latter is fubdivided fais {pherically 
curved, as in brown par; undularly curved, as in talc; 
petalo” dally curved, as in a variety of feldfpar ; and inde- 
terminately curve m 
it is either common foliated, in eran sees cover SS 
ica :—the a wei of es Turface “oF ie folia, 
ee is either {mooth or ftre 
The Paffage or — a tbe Fai ae a 
according to the number leavages into fi-gle, 
mica; double, as in feldipar. ewiienie. eo as in 
calcareous {par ; 
fame mineral, t one is contained in the other, in which 
cafe the fracture in the large is to be diftinguifhed from the 
fraQture in t 3 thus, for inftance, fi e of 
faltic hornblende, the longitudinal fraGture is ale ht fo- 
liated, while ae crofs fracture is {mall conchoidal diag 
into uneven 
- The Fo orm of “the F: ey Sita which is either i Seal or ih 
OCKe 
, a 
a aie mboidal, in hich cafe the fragments are ecalan 
1 planes, as in calcare s fpar; or fpecu four 
fides, as in feld{par ; or fpecular on two fides, qs in felenite: 
——trapezoi iated 
tainote tabula, as in mica, ine 
very fhar pene as obfidian ; tharp-ge, 
rather cna aa as lime-ftone ; bl aie as ey olin 
and ae blunt-e 
Ill. A/pea of te dj eal - bacch ghar He n& concretions 
are chats? maf i in minerals are naturally di- 
vided, and whi he can ve ‘e eee from one another thou 
breaking pier the folid or frefh part of the mineral. 
bide egos them 
m of the diftin& concretions ; it is granular, 
iatnellae, 7 colunie 
. The granular is diftinguithed, with refpe&t to form, 
into round granular, which again is {pherically granular, as 
in roe-ftone; and lenticularly granular, as in red granu 
clay iron-ftone :—angular-granular, which is either common, 
i or elongated, as in zeolite. With refpe& to 
ack —fine gra 
millet-toed. to jot je by ae naked eye; roe-ftone, 
par ry iron-ftone. 
aL ae which, with refpe& to dire€tion, is ftraight 
4L2 lamell 
ar 5 
