110 
LONG 
GALLERY. 
Nat. Hist. 
as rutile, brown iron-stone, micaceous iron, needle anti¬ 
mony, actinote, asbest, chlorite, &c.; groups of rock 
crystal ;■— amethyst quartz of various tints, in grouped 
crystals, &c. 
Case 21. Common quartz: —among the specimens 
of this widely diffused substance, which offers such 
great variety in its external aspect, the more remark¬ 
able are the hacked, corroded, and cellular quartz from 
Schemnitz, as also the pseudomorphous or supposi¬ 
titious crystals, principally derived from modifications 
of calcareous and fluor spars; and, with regard to 
colour, the blue quartz, called siderite, from Salzburg, 
and the rose or milk quartz , which are both used as 
ornamental stones;— -fibrous quartzflexible sandstone 
from the Brazil;— ironfiint . In this case are also 
deposited several varieties of stalagmitic quartz or 
quartz-sinter, the most remarkable among which are the 
siliceous concretions deposited by the celebrated hot 
spring in Iceland, the Geyser; another variety of it is 
th e 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- 
nian-sinter or those enigmatical siliceous tubes which 
were discovered in the sands of the Senner Heath in 
the county of Lippe, (where, on account of their sup¬ 
posed origin, they are called lightning tubes, from 
which name those of fulgurite, ceraunian-sinter , astra - 
phyalite , are derived,) at Drigg on the coast of Cum¬ 
berland, 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 22 contains some more of the varieties of com¬ 
mon quartz : prase, which appears to be an intimate 
mixture of this substance and actinote ;—the avanturino 
quartz; —as also some varieties of the cat's eye 
(mostly from Ceylon), in which the chatoyant lustre is 
generally produced by nearly invisible fibres of amianth 
lodged 
