REPORT OF THE DEPARTMENT OF MINERALS 

 IN THE U. S. NATIONAL MUSEUM. 1892. 



By F. W. Clarke, Honorary Curator. 



Probably no year has been more productive of good results in the 

 department of minerals than the one now ended. A large part of the 

 systematic exhibition series has been remounted on ebonized blocks, 

 replacing the former white paper trays; and soon the entire series will 

 be so displayed. Several cases of this series have been supplied with 

 printed specimen labels, and the work of labeling is still in progress. 



A large double case has been substituted for the small single gem- 

 case, so that now the collection of gems and semi-precious stones, num- 

 bering 2,215 specimens, is contained in two large double mahogany 

 cases. Of this collection 1,717 specimens are on exhibition. 



Many specimens belonging to the reserve and duplicate series had 

 accumulated in drawers stacked up in the mineral laboratory. The 

 reserve specimens have been transferred to the cases in the exhibition 

 hall, and the duplicates have been disposed of by restocking the cases 

 containing the classified duplicates, and by packing and sending the 

 remainder to storage; of these last there were 7,823 specimens. The 

 systematic duplicate series has been thoroughly overhauled and reclas- 

 sified, and it has been much improved by rejecting inferior specimens 

 and adding new and better material. This series is now used largely 

 for improving the collection by means of exchanges with other museums 

 and private collectors. During the year exchanges of 371 specimens 

 of minerals have been made with 13 different parties and 61 specimens 

 have been sent out as gifts, making a total disbursement of 432 speci- 

 mens. 



Considerable time has been consumed in selecting and preparing the 

 mineral and gem series to be exhibited at the World's Columbian Expo- 

 sition in Chicago. The scheme for this exhibit is subjoined: 



1. A series of crystallized minerals to illustrate the crystal form of 

 minerals, (a) Crystals not attached; (b) distinctive crystals on matrix ; 

 (c) crystal groups. 



2. A series illustrative of the twinning of crystals. 



3. A series to illustrate the irregularities of crystals. 



4. A series of crystalline aggregates. 



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