278 NEW ZEALAND NATURE-STUDY BOOK 
explain that this test shows the presence of a Carbonate. 
Calcite is composed of Carbonate of Lime, and is identical 
in composition with Chalk—Limestone and Marble. 
Norre.—A Comparison and contrast between these two minerals 
(Quartz and Calcite) will naturally follow the investigations just: 
concluded. 
VIII.—IRON PYRITES (FE. 8,.) 
Iron Pyrites or Iron Bisulphide is not an uncommon 
mineral in gold-mining districts, where it is usually known 
as mundic. With a little trouble good specimens can be 
obtained; specimens, that is, containing large crystals 
showing well defined crystal form. 
Notice the general shape of the specimen; the bronze- 
yellow or brass-yellow colour of the mineral ; its 
characteristic metallic lustre, and its absolute opaque- 
ness. Ascertain that it is tough and hard ; almost as 
hard as Quartz. Satisfy yourself that this is so by rubbing 
the minerals (Pyrites and Quartz) together. 
Test for fracture and cleavage—the former is uneven, 
rarely conchoidal, and the latter is wanting. 
Observe that it is crystalline, and determine the form 
of the crystals. These generally occur either as almost 
complete cubes, or as showing complete faces of cubes. 
Determine its specific gravity as in the case of other 
minerals. 
Ascertain that it is without taste or smell, that it will 
not burn, and is infusible. 
Uses.—From it are obtained certain chemical products, 
amongst the most important of which is the Sulphuric 
Acid of commerce. 
