24 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



gone on largely, the silicates are shattered, and veins of the oxidized material traverse them in every direction, pro- 

 ducing a network of fine lines, which, in thin sections, show up with a pronounced blue reflection, at first scarcely 

 distinguishable from the native iron itself. On breaking a mass open it is found to consist of metallic iron and chrysolite, 

 both easily determined by the naked eye. A polished surface exhibits interesting structural peculiarities. The 

 silicate mineral is chrysolite, which occurs in single crystals and aggregates of from 1 to 30 mm. in diameter, almost 

 universally fractured, and many of them in a decidedly sharp, angular condition. The proportional amount of iron 

 varies considerably, but as a rule constitutes one-third in bulk of the mass and performs the function of a binding or 

 cementing constituent. Schreibersite is comparatively abundant and easily distinguished by its luster from the 

 metallic iron. Troilite in sporadic patches is common, and chromite granules up to 1.5 mm. are fairly abundant. All 

 but the last named are readily distinguished, on a polished surface, by the naked eye. 



Lawrenceite exudes from the freshly cut surfaces here and there, and sometimes from the mass itself, but is most 

 abundant along the line between the iron and the schreibersite plates. Polished surfaces quickly tarnish with it and 

 must be protected by immersing in paraffin. 



The chrysolite is brecciated, a condition due not to ordinary crushing, but to a sudden change from intense heat 

 to cold or the reverse. Native iron, schreibersite and troilite often penetrate the silicates along these lines of fracture. 

 The threads or veinlets of iron and schreibersite vary from a mere line to 1 or 2 mm., and indicate beyond question a 

 solidification and perhaps reduction subsequent to the shattering of the crystals. 



The metallic minerals often occur associated in a suggestive manner. Between a broad, white, outer band of 

 nickeliferous iron and an inner area interspersed with blebs and dashes of iron, are always thin metallic plates, sug- 

 gestive of tsenite, but which chemical tests have shown to be invariably schreibersite. Often these areas quickly 

 tarnish, after polishing, and exude a greenish material which reacts for chlorine and leaves the iron beneath, when 

 washed off, of a dull black color and pitted. In such cases the material appears to be a spongy mass of metallic iron 

 and iron chloride, presumably lawrenceite. Other portions seem like spongy mixtures of iron and iron sulphide, and 

 others still, of pure iron. 



Spicules of iron on the above described areas of iron and schreibersite are seen extending from points of attachment 

 on the white metallic border inward or nearly across the interior dark gray area which is composed of lawrenceite. 

 These spicules have all the appearance of incipient stages of crystallization, where the process has been arrested before 

 completion. They resemble greatly in general appearance frost crystals on a window pane. 



Etching does not produce the Widmannstatten figures, but brings out sharply the line of demarcation between the 

 outer zone of iron and the inner, very brilliant, thin plate, which, though suggestive of tsenite, proves to be schreibersite. 



But one nickel-iron alloy exists, that most nearly corresponding to kamacite. 



No chemical analysis of the mass as a whole was attempted, owing to its extremely coarse nature and the varying 

 proportions of the metallic and silicate constituents. The chrysolite, however, yielded the following results (analysis 

 by Tassin): 



Si0 2 MgO FeO 



39.14 47.63 13.185 =99.955 



The chromite gave: 



Cr 2 3 FeO MgO Si0 2 



65.49 33.00 0.40 0.50 =100.39 



The magnesia and silica of the above probably came from the included olivine. A portion of the iron relatively 

 rich in the iron gave percentages corresponding to: 



Nickeliferous iron , 98. 273 



Schreibersite 1. 645 



Troilite 0.082 



100. 000 

 Specific gravity, 3.95 to 4.2. 



The meteorite is distributed among various collections. 



BIBLIOGRAPHY 



1. 1902: Merrill. Proc. U. S. Nat. Mus., vol. 24, pp. 907-912. 



Aeriotopos, see Bear Creek. 

 Ainsa, see Tucson. 

 Alabama, 1834, see Limestone Creek. 

 Albany County, 1859, see Bethlehem. 



Albuquerque, see Glorieta. 



