
THE COLLECTION OF MINERALS 
Barite, the sulphate of barium, is a common and widely distributed 
mineral species, frequently found in association with metallic ores as a 
vein mineral. In the series exhibited in Cases 18 and 19 many examples 
of the occurrence of barite with sulphides of lead, copper, iron and 
silver will be found. Like calcite, barite is remarkable for the great 
diversity and complexity of the crystals in which it forms; splendid 
specimens of these orthorhombic crystals are shown throughout the 
suite which is both very complete and of notably high quality. Closely 

BARITE FROM FRIZINGTON, ENGLAND 
An aggregate of flat prismatic crystals 
related to barite is the sulphate of strontium, celestite. Although some- 
times occurring like barite with metallic ores, celestite is more often 
found in close association with sulphur and gypsum: an cxample of the 
latter association is found in the specimens trom Girgenti, Sicily, a 
magnificent series of which will be found in Case 19. Celestite furnishes 
the strontium salts which are much used in the manufacture of fire- 
works, in medicines and in refining sugar. 
Anglesite (Case 19) is another sulphate which has an economic 
importance. This lead mineral is frequently found associated with 
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