25 
Sweden, frequently mistaken for hornstone; the 
weiss-stein of Werner; the feldspath compacte 
tenace of Haiiy, which is the same as the jade of 
Saussure, called by some saussurite, &c. 
{Case 12.) In this glass ca^e are deposited the dif¬ 
ferent varieties of the Labrador feldspar^ the naker- 
feldspar^ or adularia, and the coinmori feldspar ,— 
Among the specimens of Labrador feldspar (more 
properly called opalescent feldspar, being remark¬ 
able for the beautiful play of colours which it exhi¬ 
bits) are several from the transition syenite of Laur- 
wig in Norway.—The adularia (which stands in 
the same relation to common feldspar, as rock cry¬ 
stal to common quartz) is principally found on 
Mount St. Gothard, but not in the valley of Adula, 
from which its name is improperly derived :—this 
variety when cut en cabochon (such as the stone 
set in a ring) is commonly called moon-stone; mo¬ 
difications of crystals of this variety.— Common 
feldspar^ variously crystallized and massive, among 
the latter of which may be particularized the fine 
green variety from Siberia, called Amazon stone ; 
feldspar with imbedded fragments of quartz (graphic 
stone) from Siberia, &c.—To these are added a few 
specimens of disintegrated feldspar, which passes 
into porcelain earth.—The chiastolite or made, 
placed in this table, is referred by Werner to feld¬ 
spar, under the name of hollow spar.—-As interme¬ 
diate between the contents of this and those of the 
SALOON* 
Nat. Hist. 
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