\j4r EARTHS. ARGILLACEOUS. 40. Zeolhhos. 



fometrmcs k is found incloiing a drop of water: reflcils 3 

 fit-glc ci lour when held between the eye and the light: it 

 often cracks rmd becomes decompofed by expofure to the at- 

 inofphcre: contains filica 98,75. oxydeof ironOji, alumias 

 0,1. with often a little watery Klaproth, 



jidiiis^ ^emitranfparent, fhinlng very much internally, light, 



hardifli, refleding various bright colours according 

 to its politiott as to light ; breaking into acute frag- 

 ments. 



Opa U'5 Paid^rata- SvsK nat. xii. 3. p. 68^. », 6, b. 



0;alus eoio-re olivaii. Walhfyli, 1./.281. ». l^.^b. 



Opal Ed'ei. Kir'wan.nm-ier. 1./-289. 



Real OdsI. Schmeifier miner. J.^. 141. ' 



Noble Opal ^h&mjbncbevi. '^^ p^'yZZ^ 



Fouud at tliC foot of the Carpaihiafi mountains, aird in HuKgary^ 

 in folid piece'-, and fo-metimcs incorporated in other ftoness 

 colour various, the white often refledmg a yellowiih, green- 

 ifli.greenifh or rirddifli efililgCDce refembUng a Banie, when 

 placed bctweea the eye and the light, the yellow a £ery, an^ 

 the green' a purple red or yellow : whea heated it becomes 

 (opake, and is fometimes decompofed by expjfure to the at- 

 inofphere : fpecific gravity 2,1 14. caurair-s Elica 9c. water 

 JO, Klaprutb,^ 



^o. ZEOLITHUS. Gonfifting of a little alumnia, 

 arid a large proportion of fiiica^ with frequently 

 a little carbonate of lime, and a fmall quantity 

 of oxvde of iron and \Yater : lightifti, generally 

 breaking into indeternninate fragments, parafiti- 

 cal> falling fpontaneoufly into granular frag- 

 ments: foluble it nitric acid without effervef- 

 cence, and often forming with it a gelatinous 

 inafs, eafily liroching before the blow- pipe and 

 emitting a phofphorefcent light, and melting 

 into a white lemitranfparent enamel. 



^(ir'in^cens. White, friable. 



Knock Beytr, chem.amn. 2. />. 20- 



Found in hdanst and Hercvn^Uy and formed by the dccQfnpo- 

 fition and decay of other fpecies of its genus, 



Ifimlksus, Solid, fhrning internally, white witli often a fhadc of red^p 

 diaphanous, lamellarj, with the foliations undulate and 

 brittle. 



