FIRST FLOOR. 
47 
Eecently acquired specimens are shown for a time in the fifth Recent _ 
. ^ acquisitions, 
wmdow-case. 
The remaining window-cases in the gallery contain the coUec- Crystals, 
tions of crystals, models of crystals, and pseudomorphs, and are Pseudo- 
intended for the special student. The general visitor will do 
well to return to the entrance to the gallery and begin the 
examination of the table-cases, in which are exhibited speci- 
mens of every mineral species and variety in the possession 
of the Museum. The cases are numbered from 1 to 42, and General 
the eight panes of each case are distinguished by the letters Jiinerais^ °^ 
a to h. 
For the use of the student there is published a complete 
Index to the names and synonyms of all the mineral species 
and varieties represented in the Collection, with references to 
the table-cases in which specimens are placed.* 
The system of classification, which is necessarily constructed 
to include, not only ores, but all known minerals, is not very 
easy for a general visitor to follow, and it is thus convenient to 
indicate here the positions in the gallery of those minerals — as, 
for instance, precious and ornamental stones, and metallic ores 
— which have an interest for all ; for detail, reference must be 
made to the Departmental Guide. 
In cases 1 and 2 are the native metals, as Copper, Silver, Gold, 
and Platinum ; and non-metals, as Sulphur, Graphite, and Dia- 
mond. The large symmetrical crystal of Diamond, weighing 
130 carats, presented by John Euskin, is worthy of special 
attention (case Ig). 
The next six cases contain minerals which have mostly a 
metallic lustre and consist of metals in chemical combination 
with sulphur or arsenic. 
Argentite (3d) is an important silver ore, containing 87 per 
cent, of silver and 13 of sulphur. 
Blende (4b) is a valuable zinc ore, and contains 67 per cent, 
of zinc and 33 per cent, of sulphur. 
Galena (4e) is by far the most important ore of lead (lead 87, 
sulphur 13). 
Copper-glance (3e) is an important ore of copper (copper 80 
sulphur 20). 
* ' The Student's Index to the Collection of Minerals.' Price twopence. 
