4 CALIFORNIA ACADEMY OF SCIENCES. 



Composition, 2CaO, 3B 2 3 -j- 5H 2 O. 



Anhydrous boracic acid B. 2 3 [50.98] 



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 deposi- 

 tion of flakes of boracic acid in abundance. 



Locality, Southern California, where it was discovered by R. 

 Neusch wander, October, 1882. Named after Wm. T. Coleman, 

 of San Francisco ." 



In September, 1884, Mr. Evans kindly presented to me a sin- 

 gle beautifully developed crystal-fragment (Fig. 1, PI. I) with 

 permission to make a thorough study of it. From measurements 

 on this crystal, I determined the axial elements, and reckoned 

 therefrom most of the angles in the principal zones. This work 

 was about completed when I unexpectedly received from the 

 owners of tbe deposit in which the mineral occurs, about twenty- 

 five more crystal-fragments, and later still, from the State Min- 

 eralogist, Mr. H. Gr. Hanks, one more finely developed crystal. 

 The crystals thus acquired presented many new forms, and 

 enabled me to test the axial elements set up on the measure- 

 ments of the first crystal. 



Most of these crystals are quite clear and colorless, with the 

 faces in the main in very good condition. They vary in size 

 from 6 mm. in the orthoaxis, 5 mm. in the clinoaxis, by 8 mm. 

 in the vertical axis, to 30 mm. in the ortho-, 20 mm. in the 

 clino-, by 30 mm. in the vertical axis; most however being near 

 the former dimensions. One irregular individual entirely with- 

 out crystal-faces, possessed a diameter of 60 mm. Most of the 

 crystals in my possession are from medium to short columnar 

 fragments, broken from a foundation on which tbey were closely 

 aggregated as implanted crystals. Five specimens show the 

 crystals in place in thickly covered, drusy cavities in massive, fine 



