PEOCEEDIKGS 



OF THE 



ACADEMY OF NATURAL SCIENCES 



OP 



PHILADELPHIA. 



1873. 



January Y, 1873. 

 The President, Br. Ruschenberger, in the chair. 

 Twenty-nine members present. 



Trautwineite, a New Mineral. By E. Goldsmith. A mineral on 

 chi'omite, from California, was given to me for examination b^' Mr. 

 Traiitwine, who requested me to ascertain whether it was chrome- 

 green. The mineral has a green color; the hardness is between 

 1 and 2. With the naked eye the material appears to be amor- 

 phous, but, observed under high power, it proves to be crystallized ; 

 it is therefore microcrystalline. The regular forms, which I saw, 

 were short hexagonal pyramids, the infinite pyramid (prism), and 

 triangular slender prisms, which may be one-sixth sections of the 

 hexagonal prism ; I presume that this latter form is sometimes 

 called microlitic. When the substance is moistened on a glass 

 slip, covered and placed between the two crossed nicol prisms, 

 light is transmitted, with the usual phenomena of coloration. In 

 regard to colors, I may note here, that the infinite pyramid shows 

 by transmitted light a red color, but by reflected light it is green. 



Under ordinary circumstances the mineral is dull, but when 

 observed under power it appears vitreous. The streak is light 

 green. 



Pyrochemical tests: In the glass tube, closed on one end, when 

 heated to redness it shows a little water, and turus bluish-groeu. 



In borax, also in raicrocosmic salt, the material dissolves entirely 



