MINKRALOOV. 3 



the most simple form iu which il was created, although future 

 investigations may determine some of them to be compound 

 substances. 



Although the known elements somewhat exceed fifty in 

 number, the minerals aljove enumerated are almost wholly 

 composed of the following: — Silicon, aluminum, oxygen, 

 calcium, sodium, potassium, carbon and iron. In addition to 

 these may be mentioned hydrogen, as one of the two compo- 

 nents of water, and nitrogen, as one of the components of the 

 atmosphere, and chlorine, which when combined with sodium 

 forms the salt of the sea. 



It is proposed to refer to these elements first in their ori- 

 ginal form; then, secondly, in combination with oxygen, 

 and thirdly in their combination to form the minerals above 

 mentioned and including some specially used for ornamental 

 purposes, as the time at our disposal this morning will not 

 permit the discussion of much other matter connected with 

 the subject of mineralogy. 



Silicon, the most abundant of all the elements, is with 

 difficulty separated from any of its coml)inations, and it is 

 rarely seen. When combined with oxygen it forms the mineral 

 (juartz. Quartz is a hard mineral and ranks as the fourth in 

 the scale of hardness. It often occurs in transparent crystals, 

 as clear as glass, with six sides and terminated with pyramids 

 with six sides. Glass is made with quartz and soda, and the 

 sands of the sea consist almost wholly of quartz. It is one of 

 the three minerals used in the manufacture of porcelain ware. 

 Agate, chalcedony, carnelian, onyx and sardonyx are some of 

 the varieties of quartz. Wlien colored yellow, quartz is called 

 citron stone, which is sometimes sold as topaz, and when dark 

 colored it forms smoky quartz or cairngorm. When the trans- 

 parent variety is polished it is sold as a rhinestone. When 

 purple it is amethyst. When chemically combined with a 

 little water it forms the mineral opal. 



The specimen of geyserite on the table was deposited from 

 '■.he hot waters from the geysers in the Yellowstone Park. It 



