THE COLLECTION OF MINERALS 
ing jasperized wood and opalized wood. These varieties, when polished, 
exhibit very strikingly the outlines of the cellular structure of the 
wood which has thus become petrified. 
The metallic oxides are represented by a number of widely distrib- 
uted and important minerals. The copper oxide, cuprite (Case 5), 
furnishes some handsome groups of isometric crystals of cubic habit and 
deep red color. 

HEMATITE FROM ST. GOTTHARD, SWITZERLAND 
Rosettes of flat crystals 
Corundum, the sesquioxide of aluminum, with its richly colored 
varieties sapphire and ruby, also constitutes a very attractive series. 
In this instance the crystal forms consist mostly of hexagonal pyramids 
which are often highly modified. 
Hematite (Case 6), the sesquioxide of iron, is the principal source 
of that metal. The series includes a number of varieties, grading from 
the brilliant crystal groups from Elba and Switzerland to the massive 
red, loosely compacted material from the ore beds of Michigan. Mag- 
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