COMPOUNDS OF ALUMINUM. 19% 
Diff. Near beryl, but distinct in not being regularly hex- 
agonal in crystallization. 
Obs. Chrysoberyl occurs in the United States in granite 
at Haddam, Conn., and Greenfield, near Saratoga, N. Y., 
associated with beryl, garnet, ete.; in Norway, Maine. 








The name chrysoberyl! is from the Greek chrysos, golden, 
and deryllos, beryl. 
The crystals are seldom sufficiently pellucid and clear 
from flaws to be valued in jewelry ; but when of fine qual- 
ity, it forms a beautiful gem, and is often opalescent. 
Fluorides of Aluminum. 
Cryolite. In snow-white masses, having rectangular cleavages, and 
remarkable for melting easily in the flame of a candle, to which its 
name (from the Greek kruos, ice) alludes. H.=28: G.=2°'9d. Itis 
a sodium-aluminum fluoride. From Greenland. © 
Chiolite and Chodneffite are near cryolite in composition and charac- 
ters. Arksutite, Gearksutite, Pachnolite, Thomsenolite are related fiuor- 
ine compounds which occur associated with the Greenland cryolite. 
From Siberia. 
Fiuellite. From Cornwall, in minute white rhombic octahedrons. 
Contains fluorine and aluminum. 
Alunogen.—Hydrous Aluminum Sulphate. 
In silky efflorescences, and crusts of a white color, having 
a taste like common alum. H.==1°5-2. G.=1:6-1°8. 
Composition. AlO,8,+18aq = Sulphur trioxide 36-0, 
alumina 15:4, water 48°6=100. 
Obs. A common efflorescence in solfataras of volcanic 
regions, and also often occurring in shales of coal regions 
and other rocks containing pyrite ; the oxidation of the 
pyrite—an iron sulphide—affords sulphuric acid, which 
acid combines with the alumina of the shale. 
