GYPSUM. 
bender? Wern. Korniger gyps, Kart. Granularly fo- 
di io pfam, Kirw. Cape lanaary Broch. Geffa la “s 
; Fyallig gy 
Rapin 2 of colours ar foliated gyplum is, upon the 
rhe, the fame as that of the oie ub-fpecies ; white, 
, yellow, and red being its principal colours : the grey 
yellowith, —- and greenifh tints ; the yellow- 
‘occurs as wine, honey, and wax-yellow, the red as flefh, 
tile, and blood-red ; of the darker colours we have olive- 
green, hair-brown, and greyifh-black. All thefe colours oc- 
-eur fometimes punter blended in the fame fragment, in 
fpots, veins, and ftripes 
It is generally fo fo <3 smalls and diffeminated in blunt- 
: roundi{h, and kidney- 
Inodificitions of {parry gypfum or felenite. 
~ Tnternally i its luftre varies from fhining to glimmering, 
and it is moftly pearly. 
Fra&ture Selina, pecs rather curved, with fingle 
cleavage ; fometime 
sd A with oe ceed radii (ftarry gypfum). 
determinately angular, rather mer ne PY 
te 4 ular diftinét concretions of va- 
Weise ties, frees couric to very fine ular: t mall and 
-granular varieties have often fo flight a coherence, 
they can be er ope to fand by the fingers, whence 
baa eine me of “ Sandy Gypfum.” 
eoretey fcg@are often*fhows prifmatic diftine 
‘trates. 
It is more or lefs tranflucent, feldom SeenictianSparent: 
-~ is — foft, mild, eafily are see a not ob peso 
spl both i fub-fp cottwrant 
fc icep fuch 
ear m ae and Sars the Rink.tone at 
‘Enown urinows or hepatic odeury w 
Sermed Leber-ftein or Creat oh names which are 
og um or felenite impregnated with af- 
mentioned | iellneed — is found in feveral 
alfo at ———* ad 
Spathiger , Karften. 
| Kw. Fons and cal- 
fhaped pieces ; feldom in the nthe four 
imperfect doses cryitals, and fimilar to one of * 
The . 
this into pipet aut clove-brown. It oecurs alfo, though 
ys lood and of fiefh-red, and of a hrowniith-black 
pe ind ; the red is generally produced by iron 
Iti is found maffive and difleminated, feldom as coating, 
or fmall reniform : moft frequently it occurs ery 
tallized. 
All the eryflals of this fubftance we are acquainte 
may be confidered as derived from a low prifm, having for 
its bafe a rhomb, whofe angles are es pia and 53°. 
a are the principal modifica 
e mofl common and fimple is nyse which appears as 
om folid, the broad planes of which are rhombs bevilled 
that o' me 
—— Sir 33: fig. 96.) 
fix-fided prifm, having two supe planes larger and four 
ac fesallets, and bevilled on both pe the bevil- 
ling planes fet se mag but | eaak v r on the 
broader lateral p This ten-fided 2 at cryftal is 
ioe etimes clang d parallelly to the planes that meet under an 
ngle of I ometimes to thofe that meet ett an angle 
oft 111°, by sadias te cry {tal is either widened or = 
Sometimes, too, the planes that meet under an onal 
are ex of the fame width as the two rhombic siubes es, 
when the tabular is loft in the columnar form 
This modification occurs _— twin cryftals © r macle, 
(Chaux fulfatée trapézienne hémi hémitrope,) in which at one end 
a re-entering ang re 4 36". is i lateroks and one of the 
fame et but which projects its pant outward, on the 
other end. Tranfparent cryitals thus et when held 
between the eye and the light, generally exhibit the plane of 
the — as a delicate ftraight line. 
ecedi modification} in which the acute folid an- 
he Wernerian 
oh fame flat fix-fided ided prifn as the preceding, but acumi 
planes fet on the Steel edges that 
anes. 
‘ P rare modification, i is that called by ie 
- fulfatée pone g It isa kind o , ex! 
he form of an eight-fided prifm, very fatly atc, 
ree four —— oi Haiiy ii. p. 272. Pl. 34. fig. 99-) 
in cryftai, No. 1, thofe trapez: 
that meet Pang an angle of 144°, and the acute folid an ngle 
at each extremity. rounded off, wh 
other capesciall planes, meeting under an angle of LIK®, re- 
main. perfect : forms the paflage into the 
5: eR eryftals. Thefe are. either folitary or ce- 
— and confufedly grouped together with 
en ae sit ype en. 
ularly : like pet 
ofa 
part 
that remain cohering, thefe latter often 
bb fometng ke the form of lear “ semen and 
th ; 3 3 
the 
fuch a manner dah a 
he lenticular cryftals are 
rated one above The oie, 0 
‘a. 
