FIEST FLOOE. 
63 
A rich blue mineral product, the Lapis Lazuli of jewellery General 
(34b)j is brought from Persia, China, Siberia, Bokhara, and Minerab^ 
Chili; it is a mixture of various species. 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 almost ceased. 
The sulphates of strontium, Celestite (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 calcium : 
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 yields 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 calcium. 
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. 
Nitratine or Soda nitre (37d) is found in Chili in beds of 
large extent; it is largely used for the preparation of nitric 
acid and of saltpetre, and as a fertihser. 
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 
