Minerals of Rocks. 
57 
10. LIMONITE. — Limonite is sometimes known as brown 
haematite. It is softer than haematite, and in 
color is yellow or brown. 
The three more common iron-minerals can be 
compared as follows : — 
MAGNETITE 
is magnetic ; 
streak is black ; 
is very hard ; 
is not scratched by 
a knife ; 
is black ; 
is mostly in crys- 
tals ; 
is a constituent of 
basal t. 
HAEMATITE 
is not usually mag- 
netic ; 
streak is red or red- 
dish ; 
not as hard as mag- 
netite ; 
is brown or brown- 
red ; 
sometimes in crys- 
tals ; 
never a constituent 
of basalt 
LIMONITE 
not magnetic ; 
streak yellow ; 
very soft ; 
yellowish in color ; 
never in crystals ; 
never a constituent 
of basalt ; 
gives oil water wlion 
heated in a glass 
tube. 
We can now turn to the rocks composed as they 
are of the minerals described. In order to spend any 
time profitably in the study of rocks we must begin 
by seeing and handling the rocks themselves. This is 
essential. There should be no difficulty in procuring 
1. A piece of sandstone. 
2. A piece of granite. 
3. A piece of basalt. 
4. A piece of limestone. 
The specimens need not be more than one inch 
square; but, if possible, they should be in convenient 
cabinet size, say 4| by 3 by 1 inch. 
