JkNAL-YSIS OF MAGNESITB. £7| 



^>The hardaess of this stone is less than that of fl unte of Hardness, 

 lime, which scratches it ; and greatt^rthan that of calcareous 

 carbonate, which it scratches: but it effloresces at the sur- 

 face, or perhaps it is a combiuation and absorption of water 

 that takes phice, and then it becomes friable and very ten- 

 der,, so ^s to colour the fingers, and readily yi^eld an earthy 

 powder. In all cases it does not beconit; smooth wh^n rub- 

 Jbjed, or change its colour. » •: 



Its cohesion is trifling ; and it i"s;th!e raorp easj/Jf friabl*: in 

 proportion as ii contains iess of aluuiine and si lex. 

 ^.,^lts fracture is conchoid^jcli. rndiniug to even, dull, and a Fractarc 

 little rough to the touch, but never smoqiha The frag- 

 ments .have no determinate form, their angles aie more or 

 less acute. ;j , .,;^ 



^ 'Jt has.no transparency:, bijjt the thinnest edges are some- Opake. 

 Jjraes-translucid. -v,«.;i>:, ,. •-:o. ,.;■.; ^-n; w .r-htz^f^v i 



Its colour is alw;a.js,pf jajy^llowish gmjr, -ov'.'-M .^eUovvhh Coi®»r.Ti4; -jus 

 di^ty white, and black spots or figures are seen proceeding 

 from the surface to the inside. Sometimes too it appears 

 marbled with yellowish gray and biueish gray spots, parti- 

 cularly the siliceous varieties. 



When magnesite is rubbed on woollen cloth it acquires Elecuk-lty. 

 the vitreous electricity. 



It is not phosphorescent. 



It is strongly adhesive to the tongue ; and when put into AtJljcsivci^ ./ 

 water it absorbs 9 or 10 per cent, and becomes transparent ^e t«ngue. 

 at the edges, but water does not dissolve it. If triturated ter. 

 with water, it does not form an adhesive paste, but a mass 

 easily reducible to powder by drying ; and it emits a smell SmeJL 

 of magnesia, not of alumine : but the impure pieces have a 

 strong argillaceous smell, when thus treated. 



It effervesces with concentrated acids, and is dissolved by EfFervesccot 

 them,. in 24 or 36 hours ; only when it contains silex, this is 

 not dissolved- 

 lt is infusible before the blowpipe, or with the strongest Infusibis. 

 fire; but it loses its carbonic acid, contracts in its dimen- 

 sions, and grows so hard as to scratch glass. 



According to Mr. Andre, magnesite is found accompa- Where fouad. 

 nied with common and earthy talc, as well as with meer- 

 schaum, and even uiagnesian limestoiie [bilter Aa/A}, in a 

 fiiratum of serpentine in a state ^f decomposition. le 



