120 GUIDE TO THE AUSTRALIAN MUSEUM. 



The " Descriptive Catalogue of the General Collection of 

 Minerals" issued in 1885 is, up to date (1890), the only catalogue 

 of minerals published of late years by the Trustees of the 

 Museum ; it will be found useful to students and to visitors, 

 from the amount of information it contains on the subject. 

 There are about 2340 specimens numbered and about 400 which 

 have been purchased since the issue of the catalogue, and not 

 yet numbered ; some of them being very remarkable for their 

 size, beauty, or rarity. 



I.— GENERAL COLLECTION OF MINERALS. 



The arrangement adopted for this collection has been fully ex- 

 plained in the catalogue. 



In some systems of mineralogy, prominent importance is 

 given to certain laws based on the proportions of the com- 

 bined elements, and to the molecular arrangement of these 

 elements in connection with the crystalline form. It is easy to 

 understand, however, that, if this system be adhered to, any 

 particular metal sought for by the practical man is likely to 

 appear in different sections, widely apart from each other, ac- 

 cording to the classes of combinations in which it occurs. For 

 instance, Garnierite (the Nickel ore of New Caledonia, which is 

 a silicate), Chrysocolla (silicate of copper). Electric Calamine 

 (silicate of zinc), Rhodonite (silicate of manganese), in such 

 systems, are distributed in different groups among the Silicates ; 

 while in the system adopted here, these minerals will be found 

 respectively in the Nickel class, in the Copper class, in the Zinc 

 class, and in the Manganese class among the Metallic Minerals. 

 It does not always follow, however, that the mineral considered 

 should be a workable ore of the metal in which class it has been 

 placed. Sulphide of Iron, or Iron Pyrites, is worked for gold and 

 for sulphur, but not for iron ; still it belongs to the Iron class. 

 Whenever it has been found convenient to represent an important 

 mineral in more than one class, it has been done. 



The minerals are divided into two main sections (see Catalogue, 

 pages 9 to 12), viz. : — 



