FIRST FLOOR. 
61 
such as the lining of iron safes, packing for steam-pipes and General 
boilers, and in gas-stoves ; for these purposes its low con- ffiStSS? ot 
ductivity for heat renders it very serviceable. 
Jade or Nephrite (24d), a much valued mineral, belongs to 
the same mineral group as hornblende. It has few known 
localities, and it has been difficult to find an answer to the 
question as to whence the older workers of jade can have got 
their material. The various shades of colour and the beautiful 
polish which this tough mineral will take are illustrated by 
specimens in the case. The worked specimens from New 
Zealand, of which there are several exhibited, are now rare. 
An immense water- worn mass, found some years ago in Asiatic 
Eussia, is shown in the Pavilion. 
Meerschaum (23g) is the light soft porous mineral used for 
tobacco-pipes : it is a hydrated silicate of magnesium. 
Serpentine (25a) is another hydrated magnesium silicate : the 
ease with which it is worked and takes a good polish, its green 
colour, and varied markings render it much sought for as a 
material for fire-places, tables, and other indoor work : exposed 
to the weather it soon loses its polish. Only specimens illustrat- 
ing the purer forms of the mineral are shown in the case. 
Topaz (25d) in its clear varieties is one of the precious stones. 
The crystals from the Urulga river, in Siberia, are remarkably 
fine examples of crystalline development ; they are of a delicate 
brown colour, but are kept covered up, as the action of light 
speedily bleaches them. The yellow crystals from Brazil assume 
a peculiar pink colour when heated, and are then known to 
jewellers as Burnt or Pink Topaz. 
Garnet also belongs to the group of precious stones ; when 
the red is tinged with violet, it is the Almandine and the Syrian 
garnet (from Syriam in Pegu), and when cut en cabochon, the 
Carbuncle of jewellery (2 6f ) ; the Cinnamon-stone or Essonite 
is yellow (26e) ; the Pyrope and the Bohemian garnet are 
blood-red (26e) ; Uvarovite is a green chrome-garnet (26h). 
Jadeite (27a) is one of the green stones, which, under the 
name of jade, are wrought into ornaments in China : from jade, 
however, it is distinguished by its chemical composition, struc- 
ture, and higher specific gravity. 
Among the specimens of Epidote (27c) a remarkable suite 
from the Untersulzbachthal is exhibited. 
