19 
from Schemnitz, as also the pseudomorphous or 
supposititious crystals, principally derived from 
modifications of calcareous and fluor spars; and, 
with regard to colour, the red quartz crystals from 
Compostella, imbedded in gypsum, and known by 
the name of hyacinths of Compostella; the siderite 
from 'Salzburg; the blue quartz of Orrayervi in 
Finland, called steinheilite .—Among the varieties 
of quartz is the rose or milk quartz^ which occurs 
only massive, the prase, which appears to be an in¬ 
timate mixture of common quartz and actinote.— 
In this case are also deposited some varieties of the 
cafs-eye (mostly from Ceylon): a substance gene¬ 
rally referred to the natural order of quartz. 
{Case 6.) Besides some specimens of substances 
related to common quartz, such as the avanturmo 
quartz^ the flexible sandstone from Brasil, and the 
iron-flint (a substance in which oxide of iron exists 
in chemical union with silica), this case contains 
varieties of the stalagmitical quartz^ also called 
quartz sinter. The most remarkable among these 
are the siliceous concretions deposited by the cele¬ 
brated hot spring in Iceland, the Geyser, and which 
are distinguished into siliceous tuj] and calcedonic 
sinter. Another variety of it is Xhc^ jjeaid sinter from 
Santa Fiora in Tuscany (whence it obtained the 
name of Fiorite), and from the island of Ischia. 
To this may also be referred the ceraunian sintery 
or those enigmatical siliceous tubes, which were first 
c 2 found 
saloOn. 
Nat. Hist. 
