THE COLLECTION OF MINERALS 
shown here (Desk Case 1) in sheets like rolled metal; in plates, 
with crystallized edges; in braided filaments made up of minute 
octahedrons; in grouped octahedrons with hollow faces; in 
twisted plates frequently attached to quartz, around which it 
curls like some irregular yellow flower. Gold, from an elongation 
of the octahedron, assumes deceptive forms, while cavernous, 
skeleton and pitted crystals, peculiar distortions, reticulated 
and tree-shaped groups with spongy masses and rounded water- 
worn nuggets are common natural appearances of this precious 
metal. 
Copper (Desk Case 1) is of especial interest, on account of the 
beautifully crystallized specimens in which it occurs. Most of 
our specimens have come from the remarkable deposits of Native 
Copper in the Lake Superior region of Northern Michigan. They 
exhibit the characteristic crystal forms of the metal, sprigs and 
branching crystals, twins and massive plates, the common tetra- 
hexahedron, cubes and superimposed octahedrons. Here will be 
found also examples of Copper and Silver which have been welded 
together by nature. 
The next group of minerals is that comprising the Sulphides, 
Selenides and Tellurides of the metals and semi-metals, and the 
Arsenides and Antimonides of the metals, which are again suc- 
ceeded by the so-called Sulpho-salts, in which the union of sul- 
phur with arsenic or antimony is regarded as an acid, chiefly 
forming compounds with the bases, copper, silver, lead, iron, 
zinc and mercury. The great variety and number of mineral 
species resulting from the combinations thus made possible, are 
for the most part the source of many useful metals, and these 
combinations characterize the veins, crevices, fissures, caves 
and beds of mining regions. 
One of these, Stibnite, the sulphide of antimony, is a valuable 
ore (Desk Case 1,Wall Case A). This species affords the mineralo- 
gist very beautiful, lustrous, well-terminated prismatic crystals, 
usually clustered in radiating groups. The striking specimens 
here displayed, together with many others which have supplied the 
cabinets of the world, were found at Mt. Kosang near Seijo, pro- 
vince of Iyo, Shikoku Is., Japan. In their size and beauty and 
sie) 
