THE MINERALOGICAL COLLECTIONS IN THE U. S. NATIONAL 



MUSEUM. 



By Wirt Tassin. 

 Assistant Curator, Department of Minerals, U. S. National Museum. 



A mineral collection in a public museum should present all of the 

 detinite varieties of minerals occurring ready formed in nature, their 

 associations with other minerals, their occurrences, and finally their 

 chemical, morphological, and other i^hysical features. It must meet 

 the needs of the chemist, the crystallographer, the j)hysicist, the geolo- 

 gist, the petrographer, the student, and the observer who may desire 

 to obtain concise and specific information in any and all branches of 

 mineralogy, and finally it should be a university extension of the 

 broadest kind where one may secure a knowledge of minerals from 

 the cases with as little reference to the library as i)Ossible. 



With these ends in view the mineralogical collections of the National 

 Museum are divided into three general series — the exhibition series, 

 the study series, and the duplicate series. The first of these, the exhi- 

 bition series, is primarily intended for the public and the student. It 

 is divided into two parts — the systematic series and the comparative 

 series. 



THE SYSTEMATIC SERIES. 



The systematic series treats of the properties of minerals in their 

 relations to the several kinds of minerals, and the description and sys- 

 tematic arrangement of the several species. Here will be found the 

 several rei)resentatives of the mineral kingdom, selected to illustrate 

 occurrence, association, color, and typical development. Here too are 

 to be found the rough and cut specimens of gems and ornamental 

 stones, tlie collection of meteoric bodies, and the "special locality" 

 collections illustrating certain regions in the United States where a 

 mineral or a series of minerals occur under noteworthy or special 



conditions. 



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