CALIFORNIA ACADEMY OF SCIENCES. 59 



Colemanite. — Ciystallizatioii rnonoclinic. ^Inclination of 

 the vertical to the clinodiagonal axis (C) 70i° I a I 108^ c . 

 ii A I 144|° ii a I 126 J°. Luster vitreous to adamantine, 

 often splendent! Cleavage ii or clinodiagonal , perfect, af- 

 fording readily thin, smooth and polished laminae which 

 often show interference figures. Cleavage in other planes 

 imperfect and fracture uneven, giving surfaces of a subvit- 

 reous luster. Hardness 3.5 in the amorphous, to 4.25 in 

 crystalline variety. Sp. gravity 2.428. Colorless. Streak 

 white. Transparent, subtranslucent to milky, especially in 

 the massive. Rather brittle. 



Composition. 2CaO, m, 3 + 5H 2 0. 



Anhydrous boracic acid B 2 3 [50. 9S] 



Lime CaO 27 18 



Water 21.84 



Total 100.00 



Pyr. Decrepitates violently and at length sinters. With 

 fluor spar and bisulphate of potash, colors the flame yellowish 

 green, Soluble in dilute hydrochloric or nitric acid with 

 deposition of flakes of boracic acid in abundance. 



Locality, Southern California, where it -was discovered by 

 R. Neuschwander, October, 1882. Named after "Win. T. Cole- 

 man of San Francisco. 



*The notation is conformable to that of Dam's system of mineralogy. The measure- 

 ments were made with hand a goniometer, and subject to the ordinary errors. 



