86 Properties of Minerals. 
and forty-five mineral species. In order that the young 
student may make rapid progress in the study of the 
science of mineralogy, the following suggestions are of- 
fered for his benefit: In the first place he should se- 
cure a good working collection of well selected minerals, 
accurately determined and labeled.( For which see page 
182). With a working collection of 100 or more spe- 
cimens the student should next familiarize himself 
with the use of the blowpipe, and to this end he should 
reproduce or verify as many as possible (or ail) of the 
blowpipe tests given on pages 54 to 81. The blowpipe 
outfits described on page 46 and page 178 are especially 
recommended for his use. Mineral specimens illustrat- 
ing the scales of lustre, color, hardness, fusibility, erys- 
tallization, etc., (as described below and given on page 
178), should by all means form a part of his outfit. 
We will now proceed with a description of the phys- 
ical properties of minerals, and after fully describing 
the nature of these properties, we will arrange them in 
tables with the names of the mineral species in accord- 
ance with the degree of which the respective species par- 
take of these properties. 
FIRST PROPERTY. 
COMPOSITION. 
Minerals differ in their chemical composition, 
and in extreme cases even quantitative chemi- 
cal analysis must be resorted to in order to dis- 
tinguish them. ‘The qualitative blowpipe tests (page 
54) will in general be found fully sufficient to indicate 
the chemical composition of mineral near enough for 
all practical purposes of identification. It should here 
be borne in mind that minerals are of definite chemical 
. composition, while ores, like rocks (page 149), may con- 
sist of two or more minerals. In testing a mineral, 
