EXHIBIT AT THE COTTON STATES EXPOSITION. 62'3 



from various localities; second, to the compounds of gold with silver, 

 tellurium, antimony, and sulphur as shown in the minerals petzite, syl- 

 vanite, krennerite, and nagyagite; third, to the occurrence of the 

 native metal with its associates, either as dust or nuggets in sand and 

 gravel, or impregnating quartz, slate, calcite, and other minerals form- 

 ing the characteristic gangue, and lastly to the series of gold ores, rep- 

 resenting the metal-bearing rocks as usually mined, and which, while, 

 as above noted, showing no trace on casual inspection of the precious 

 metal, nevertheless contain it in sufficient amount to render its extrac- 

 tion by chemical or mechanical means a profitable industry. 



The silver-bearing series is arranged in a similar manner. It is to 

 be noted that while gold is common in deposits of sand and gravel, as 

 "placer gold," silver very rarely occurs in this form, and is represented 

 here only by the silver-bearing sandstone from Washington County, 

 Utah. Native silver in the form of "wire" or "moss" silver is, how- 

 ever, comparatively common, as shown in the specimens from Mexico 

 and Saxony. Some of the silver-bearing compounds are of great 

 beauty, as illustrated in the ruby silvers, proustite and pyrargyrite. 



The total annual production of gold and silver for the world for 1894 

 is given as 8,616,892 ounces of gold, and 166,437,408 ounces of silver. 



DEPARTMENT OF MINERALS. 



This department (Alcove G-), was represented by a collection of high 

 educational importance, arranged by Mr. Wirt Tassiu, under the direc- 

 tion of Prof. F. W. Clarke, the curator, and is described as follows: 



Entering the alcove the wall cases contain a series of minerals 

 selected and labeled to illustrate the several properties or characters 

 of one mineral species as compared with other mineral species, in other 

 words, " comparative mineralogy." 



The first case on the left contains a series of 143 minerals illustrating 

 chemical mineralogy; that is, the composition, variation in composi- 

 tion, and the relation of composition to form of minerals. 



The chemical composition of minerals is illustrated by several typical 

 elements together with a majority of their combinations. It will be 

 observed that gold has comparatively few combinations, and that its 

 occurrence is practically restricted to the element; while iron, the most 

 useful of the heavy metals, rarely occurs as the element, yet affords a 

 great number and variety of compounds. 



Proceeding from left to right, the next case contains a series of models 

 and specimens illustrating the principal forms of minerals depending 

 upon molecular structure of form. 



Beginning with the system of crystallization each system is repre- 

 sented by a typical crystal group followed by models and specimens 

 showing the principal forms belonging to that system. 



For example, fluorite, a typical isometric mineral, is shown, then a 

 glass model of the fundamental isometric form, the octahedron, and 

 spinel; a typical octahedral mineral. Following the system of crys- 

 tallization are crystal aggregates, including twin crystals, parallel 

 growths, and imperfections of crystals. 



The next wall cases contain series illustrating isomorphism, pseudo- 

 morphism, and the various characters depending upon the action of 

 the several physical forces, such as light, cohesion, mass, heat, etc. 



The floor case on the left contains several minerals, arranged to show 

 the great diversity and beauty of their coloring. 



