Ramosite not a Mineral; by Lea Mel. Luquer. 
(From American Journal of Science January 1904). 
The doubtful mineral Ramosite occurring in pebbles in alluvium from 
San Luis Potosí, México, originally described by Perry in the Transac- 
tions of the American Institute of Mining Engineers in 1884 (vol XII, 
628), has been carefully reexamined with the following results. 
Sections were obtained with great difficulty on account of the ex- 
treme hardness and brittleness, but proved the material to be greenish 
by transmitted light, non-pleochroic and isotropic and gave no indication 
of erystalline structure. Irregular fracture lines were common. sometimes 
approaching in appearances cleavages, and many minute shot-like grains 
of an iron-stained decomposed mineral were noticed. 
The region in which the material occurs is volcanic, and the very 
marked vesicular structure nd conchoidal fracture would indicate a vol- 
canic scoria. The hardness from 8-9 is unusual, but basic seorias from 
the Sandwich Islands and elsewhere have shown a hardness from 6-7, 
greater than that of ordinary obsidian. The recorded analysis, for which 
no great accuracy is claimed, shows: 
SiO? Fe» Oz Al> Oz3 Ca0 MgO MnO» 
46.32 13.00 9.19 17.74 13 13 trace = 99 88, 
corresponding rather closely to formula R2 03 4RO. 5 SiOz. The mate- 
rial qualitatively resembles garet, but quantitatively differs widely; 
thus removing the possibility of it being a kind of garnet (as suggested 
by Dana). 
The analysis of a tachylyte from Gethurms, Germany, by Lemberg, 
shows: 
SiO» Fes 03 Al203 Ca0 MgO K,0 N20 Loss 
45.13 — 12.46 20.15 8.67 3.59 - 4.11 5.74 0.12=100.57 
as low in SiO» as the supposed Ramosite. 
The evidence, therefore, shows the material to be not a mineral, but 
a basic scoria of unusual hardness and composition. 
Department of Mineralogy, 
Columbia University, N. Y., Nov. 4, 1903. 
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