346 Bowen's Analysis of the Nephrite. 



fessor Silliman, at one of the marble quarries, near New- 

 Haven, and his opinion was that this mineral coincided ex- 

 actly with the Swedish Sahlite or Malacholite. 



Art. XVII. — Analysis^ of a variety of Nephrite, from 

 Smithfeld, R. I. By George T. Bo wen, of Providence. 



This beautiful mineral occurs at Smithfield, imbedded in 

 large nodules in wliite primitive limestone. Its color is bright 

 apple green — sometimes tinged with blue ; the colour of 

 its powder is white — its hardness is equal to that of felspar — 

 its fracture dull and splintery — it is highly translucent, and 

 very difficult to break on account of its great tenacity — be- 

 fore the blowpipe it is infusible. Its specific gravity varies 

 from 2.594 to 2.787. — Its powder when boiled with sul- 

 phuric or nitromuriatic acid, is entirely decomposed; the 

 obtained solution yielding an abundant precipitate with 

 Phosphate of soda and ammonia. 



Analysis. 



A. Fifty grains of the mineral in the powder were ex- 

 posed, during thirt} minutes, to a red heat in a platina cru- 

 cible ; the colour of the powder was not altered. The 

 weight after calcination was 43.250 grains; the moisture 

 dissipated amounted therefore to 6.750 grains in 50 grains, 

 or 13.500 per 100. A piece of the mineral weighing 100 

 grains was then heated during thirty minutes, without having 

 been reduced to powder. Its green colour disappeared; it 

 lost its translucency, and became of a pure white ; its hard- 

 ness was also much increased as it now scratched glass with 

 facility. The loss of weight amounted to 13.625 grains. 

 The mean of three experiments gave as the loss by calci- 

 iaattons 13.417 grains per 100. 



B. One hundred grains of the mineral in powder were 

 fused with 300 grains of caustic potash, in a silver crncible, 

 and kept at a red heat during one hour. The contents of 

 the crucible, when removed from the fire, were of a light 

 green colour. — Muriatic acid was added in excess, and the 

 fluid evaporated to dryness. — The dry mass was then treat- 

 ed with water acidulated with muriatic acid ; the silex sep- 



"^ Done iq tlie Laboratory of Yale College. 



