FIRST FLOOR. 
63 
Haiiynite (34b), in its rich blue variety, is the Lapis Lazuli General 
of jewellery, and is brought from Persia, China, Siberia, and Mineral 
Bokhara. When powdered, lapis lazuli furnished the once 
costly pigment ultramarine ; through the discovery of a method 
of producing an artificial and cheap form of the same material, 
the use of the mineral as a pigment has been quite superseded. 
The sulphates of strontium, Celestine (35c), of barium, Barytes 
or Heavy Spar (36a), and of lead, Anglesite (36e), are all repre- 
sented by long series of specimens. 
Gypsum or Selenite (36f) is the hydrated sulphate of lime : 
when heated it gives up its water of crystallisation and falls to a 
white powder, known as " Plaster of Paris " ; when moistened 
the powder again combines with water and forms a coherent 
solid. A magnificent crystallised specimen, a gift from the late 
Prince Consort, will be found in the Pavilion. Gypseous ala- 
baster is a massive variety of gypsum (36h) ; owing to its white- 
ness, fine texture, and softness, it is largely used as a material 
for statuettes and other indoor ornaments ; the Oriental ala- 
baster is a harder substance, stalagmitic calcite, the carbonate 
of lime. 
Borax (37c) is a hydrated borate of sodium. It is much used 
as a flux, also in the process of soldering, and in the preparation 
of easily fusible enamels. It was formerly carried over the 
Himalayas from a lake in Thibet, but is now obtained largely 
from borax lakes of the United States, and is extensively pre- 
pared from the boracic acid of the lagoons in Tuscany. 
Mtratine or Soda nitre (37d) is found in beds extending for 
many miles ; it is used for the preparation of nitric acid and of 
saltpetre, and now largely as a fertiliser. 
Calaite or Turquoise (38g) is a hydrated phosphate of alumi- 
nium ; it owes its blue or green colour to the presence of small 
quantities of salts of copper and iron. Being as hard as felspar 
and taking a good polish, it has been much prized in jewellery 
under the name of Oriental Turquoise ; that which comes into 
the market is chiefly brought from the turquoise mines, not far 
from Nishapur, in Persia. 
As a supplement to the collection of simple minerals, there is 
arranged, in case 41, a group of natural substances which 
either belong or are closely related to the Mineral Kingdom, 
