PART III. 
DETERMINATIVE MINERALOGY. 
The Determination of Minerals by Their Physical Prop- 
erties With the Aid of Tables. 
Physical Properties of Minerals——To make an off- 
hand determination of the more common minerals met 
with is an attainment easily acquired; and it is an art 
in which the intelligent prospector, miner, and mining 
man should become expert. 
While in nature there are minerals so nearly iden- 
tical in their physical characteristics as to require even 
chemical analysis in order to distinguish them, in the 
majority of cases, however, it will be found, that on 
close examination, marked differences may be discerned 
and of sufficient prominence, to at once distinguish any 
one species from any other to which it may at first bear 
. a striking resemblance. 
Minerals differ—(1) In their action before the 
blowpipe (B. B.). (2) They differ in Lustre. (3) 
Color. (4) Hardness (H.). (5) Streak. (6) Fracture 
and cleavage. (%) Tenacity. (8) Crystalline system 
(Crys. Syst.). (9) Fusibility (Fusib.). (10) In Spe- 
cific Gravity (G). These distinguishing characteristics 
of minerals are described below in the order in which 
they appear in the Analytical Tables of minerals (Page 
95). These tables afford all necessary data (when 
taken in connection with the blowpipe tests, page 46) 
for the accurate determination of some three hundred 
