NON-METALLIC MINERALS. 
117 
forming minerals Augite or Pyroxene and Hornblende or 
Amphibole. 
Jade or nephrite is well known as a mineral which, in spite 
of its hardness, is largely carved into images and ornaments of 
various kinds by the Chinese ; and it was also worked by the 
Maories of New Zealand. It should he mentioned, however, 
that at least two distinct minerals were formerly confounded 
under the general name of jade. The true jade is essentially a 
silicate of calcium and magnesium, being in truth a hornblendic 
mineral, while the species jadeite, often mistaken for it, is a silicate 
of aluminium and sodium. The name nephrite is derived from 
the Greek nephros, kidney — in allusion to its having been used 
by some peoples for the cure of diseases of that organ. Some 
fine Chinese carvings in jade and jadeite are in Case 54. 
The fibrous forms of hornblende and similar minerals are 
known as Asbestos ( inconsumable ), from their power of resisting 
the action of intense heat ; hence asbestos cloth, woven from the 
fine threads, may be exposed to fire without ,being consumed. 
The delicate fibres are distinguished as mountain silk, while the 
massive forms resulting from the interlacing of these fibres are 
called, according to their texture, mountain leather, rock cork, 
&c. Asbestos is now extensively employed as a material for 
jacketing steam-pipes, for fire-proof roofing and flooring, for 
packing safes, &c. Much of the asbestos, such as that from 
Canada, is a fibrous form of serpentine, known as chrysotile. 
Case V.— -Mica; Steatite; &c. 
The members of the Mica family, of which many representa- 
tives are exhibited, differ from one another in optical and other 
physical characters, as also in chemical composition. They are 
important as constituents of granite, mica schist, and other rocks. 
A portion of an unusually large crystal of Canadian mica 
( phologopite ) will be found in the lower part of the Central 
Case, with the Australian model, in the Model Room A. (p. 135 \ 
The mica-group is usually divided into two branches, known 
as the light and the dark micas ; the former being represented 
by the common species muscovite, or potash-mica, and the latter 
by biotite, a ferro-magnesian mica. All the micas contain more 
or less water, and stand perhaps intermediate between the 
hydrous and anhydrous silicates. In the mica-like minerals 
forming the group of chlorites combined water is always 
present, usually to the extent of upwards of 10 per cent., and 
the minerals are true hydrates. 
In this Case will be found the familiar Meerschaum (“ sea 
foam”) or Ecume de mer , so called in allusion to its lightness 
and white colour. This is a hydrous silicate of magnesium, 
found in Asia Minor, Turkey, Greece, &c. 
Another mineral exhibited here is Steatite which frequently 
occurs in association with serpentine, as in the Lizard District 
