y 



X .X 



THE OREGON NATURALIST, 



Vol. III. Portland, Oregon, March, 1896. No. 



NOTES ON A NEW ALKALI mimetical pyrite, Bologna, 1893.) The 



MINERAL. markings in the present instance are prob- 



— ably due to inclusion of organic matter, 



Mr. C H. Northup, of San Jose, [Cal.] as in chiastoiite. 



while searching at Borax Lake, Cal- The color varies from dirty white, pale 



ifornia, for the new species sulphohalite, yellow and greenish gray to dark brown; 



discovered small crystals of what he con- the lighter colored crystals closely resemble 



sidered to be a new form of that mineral senarmontite. Cleavage is imperfect It 



and is described in the Mineral Collector, is brittle and shows uneven fracture, 



as follows: Luster, vitreous on broken surfaces, oc- 



Crystallization, etc— The mineral casionally bright on crystal planes, 



crystallizes in regular octahedrons, Hardness 3.5 to 4. 



whose diameter rarely reach one centi- Chemical examination.— in powdering 



meter. They occasionally exhibit triang- the mineral a fetid odor is distinctly per- 



ular markings and a habit of parallel ceptible. It is easily fusible before the 



grouping in more or less regular aggre- blowpipe; in the closed tube it blackens 



gates. Fractured crystals show in the and gives off a burnt odor with violent 



interior a cross of faint lines running per- decrepitation and liberation of water 



pendicularly to the crystal faces. These (which subsequently proved to be me- 



aredividedby darker planes lying parallel chanically included,) finally fusing to a 



to cubic symmetry, and passing through gray mass. Boiling water effects partial 



the angles of the octahedron, dividing it decomposition of the powdered mineral, 



into eight parts. The same thing is with separation of a bulky white residue, 



noticeabl** in the clearest of the complete consisting mainly of basic carbonate of 



crystals, a bundle of strije coming from magnesia. It is decomposed with efferv- 



the center of the crystal to the center of escence in cold dilute hydrochloric acid, 



each face with the dividing planes clearly with slight residue insoluble, 



visible. This phenomenon is strikingly A careful qualitative analysis of crystal 



similar to that observed in cubes of boleite fragments showed it to consist essentially 



(figured by Bombicci in a memoir on of sodium, magnesium, hydrochloric and 



