tib CHEMICAL PROPERTIES OF MINERALS. 



TASTE. 



Taste belongs only to the soluble minerals ; the kinds aro— 



1. Astringent: the taste of vitriol. 



2. Sweetish-astringent : the taste of alum. 



3. Saline : taste of common salt. 



4. Alkaline : taste of soda. 



5. Cooling : taste of saltpeter. 



6. Bitter : taste of epsom salts. 



7. Sour : taste of sulphuric acid. 



ODOR. 



Excepting a few gases and soluble minerals, minerals in 

 the dry, unchanged state, do not give off odor. By friction, 

 moistening with the breath, the action of acids and the blow- 

 pipe, odors are sometimes obtained, which are thus designated : 



1. Alliaceous : the odor of garlic. It is the odor of burn- 

 ing arsenic, and is obtained by friction and more distinctly 

 by means of the blowpipe from several arsenical ores. 



2. Horse-radish odor : the odor of decaying horse-radish. 

 It is the odor of burning selenium, and is strongly perceived 

 when ores of this metal are heated before the blowpipe. 



3. Sulphureous : odor of burning sulphur. Friction will 

 elicit this odor from pyrites, and heat from many sulphurets. 



4. Fetid : the odor of rotten eggs or sulphuretted hydrogen. 

 It is elicited by friction from some varieties of quartz and 

 limestone. 



5. Argillaceous: the odor of moistened clay. It is given 

 off by serpentine and some allied minerals when breathed 

 upon. Others, as pyrargillite, afford it when heated. 



CHAPTER IV.— CHEMICAL PROPERTIES OF 

 MINERALS. 



ACTION OF ACIDS. 



Acids are used in distinguishing certain minerals that are 

 decomposed by them. The acids employed are either the 

 sulphuric, muriatic, or nitric. Carbonate of lime, (calca- 



What taste is astringent ? sweetish astringent 1 saline ? What wiK 

 develop odor in some minerals? What is understood by an alliaceous 

 odor 1 What mineral when heated produces this odor ? What is the 

 odor of fumes of selenium 1 How is a sulphureous odor obtained from 

 certain minerals 1 What gas has a fetid odor ] What is an argilla- 

 ceous odor ? 



