139 
veral varieties of stalagmitic quay'tz or quartz- 
sinter, the most remarkable among which are 
the siliceous concretions deposited by the cele¬ 
brated hot spring in Iceland, the Geyser; an¬ 
other variety of it is the pearl-sinter from Santa- 
Fiora in Tuscany, (whence it has obtained the 
name of fiorite,) and from the island of Ischia. 
With these are placed specimens of the cerau- 
man-sinter or those enigmatical siliceous tubes 
which were discovered in the sands of the Senner 
Heath in the county of Lippe, (where on ac¬ 
count of their supposed origin, they were called 
lightning tubes, from which name those of 
fulgurite , ceraunian sinter , astraphyalite , are 
derived,) at Drigg on the coast of Cumberland, 
and latterly, by the late Capt. Clapperton, near 
Dibbla in the Tuarick country, Africa, from 
which localities specimens are here deposited. 
The hyalite is placed here as a mineral related 
both to stalagmitic quartz and calcedony. 
Case 21 contains some more of the varieties 
of common quartz : prase , which appears to be 
an intimate mixture of this substance and acti- 
note ;—the avanturino quartz ;—as also some 
varieties of the cat’s eye (mostly from Ceylon), 
in which the chatoyant lustre is generally pro¬ 
duced by nearly invisible fibres of amianth 
lodged in the quartzy mass.—Part of this case 
is occupied by the siliceous substance called 
hornstone, divided into the conchoidal and 
splintery 
LONG 
GALLERY. 
