*34 
EARTHS. ARGILLACEOUS. 40. Zeolithus. 
fometimes it is found inclofing a drop of water: reflects * 
Angle criour when held between the eye and the light; 
often cracks and becomes decompofed by expofure to the at' 
mofphere: contains filica 98,75. oxyde of iron c,i . alumin* 
0,1. with often a little water, Klaproth, 
nohihs, Semitranfparent, fhining very much internally, lighh 
hardilh, refleiSing various bright colours according 
to its pofition as to liglit : breaking into acute frag- 
ments. 
Opaiub Pxdorat^- Sfst, nat. xii. 3. p. 68. n. 6, b. 
Opalus colorc olivati. Wall,fyfl. 1. /), 281. n. 19. b. 
Opal Ed^er. K/r-ujan miner, 289, 
Real Opal. Uchmeifser miner, l.p. 141, 
Noble Opal Thomj'onchem. 3.^. 522. 
Found at the foot of the Carpathian mountaini, and in Hungary! 
in folid piece-, and fometinics incorporated in other Honest 
colour various, the white often refleching a yellowifli, green- 
ilh-grcenilh or reddilh effulgence refcmbling a flame, when 
placed between the eye and the light, the yellow a fiery, and 
the green a purple red or yellow; when heated it becomes 
opake, and is foinctimes decompofed by expofure to the at' 
mofphere: fpecific gravity 2,1 14. conrains filica 90. waief 
f O, Klaproth. 
40. ZEOLf THU.S, Confiding of a little alumina, 
and a large proportion of filica, with frequently 
a little carbonate of lime, and a fmall quantity 
of oxyde of iron and water: lightifh, generally 
breaking into indHerminate fragments, parafiti- 
cal, filling fpontaneoufly into granular frag- 
ments ; foltible i-i nitric acid vyithout effervef- 
cence, and often forming with it a gelatinous 
mafs, eafily frothing befoie the blow- pipe and 
emitt.ng a phofphorefcent light, and melting 
into a white femitranfparenc enamtl. 
farinaceus. White, friable. 
Knock Beyir. chem, ann. 2. p. 20- 
Found in Icelana and lltrcr'’a, and formed by the decompo- 
fition and decay of other fpecies of its genus. 
lamellosus. Solid, (hining internally, white with often a fhade of red, 
diaphanous, lamellar, with the foliations undulate and 
brittle. 
