NATURAL HISTORY. 
57 
GALLERY. ] 
mens of comptonite from Vesuvius, lining the cavities of a pyroxenic 
lava, &c., accompanied by gismondine and other crystallized substances; 
together with thomsonite , which is supposed to be only a variety 
of comptonite ;—gmelinite or hydrolite ;— levine, and some other scarce 
zeolitic substances. 
Case 29. To the same family of minerals belongs the prehnite, the 
grass-green variety of which, discovered in South Africa by the Abbe 
Rochon, has been mistaken for chrysolite, chrysoprase, and even emerald; 
—to this also belongs the koupholite of Vauquelin. The substance known 
by the name of Chinese jade or you-stone , (kyonk tshein of the Bur¬ 
mese,) is likewise placed with prehnite, to which it has been referred by 
Count Bournon; but no chemcal analysis has as yet been given of it. 
(Among the vessels wrought out of it on this table is a cup, the 
gift of the king of Ava to Lieut.-Col. Burney when British Resi¬ 
dent at that court, and by him presented to the British Museum.) 
With this is placed the harmotome or cross stone, (also called 
andreolite, after Andreasberg, in the Hartz, where it was first dis¬ 
covered,) divided into baryte-harmotome and potass-harmotome, to 
which latter are to be referred the Vesuvian minerals called zeagonite , 
gismondine , abrazite, and also the philipsite . ( Of andreolite, a magnifi¬ 
cent specimen is deposited, presented by King George IV.) The re 
maining space in this Case and 
Cases 30 and 31 will be occupied chiefly by feldspathic substances and 
minerals more or less nearly related to feldspar. The most remarkable 
and important species is the common feldspar , among the crystallized and 
massive varieties of which maybe particularized—the fine green variety 
from Siberia, called amazon stone ; the beautiful large crystals from 
Baveno ; feldspar with embedded crystals and fragments of quartz (gra¬ 
phic stone, graphic granite), from Siberia, & c.;—the Labrador feldspar 
(also called opalescent feldspar, from its often exhibiting a beautiful play 
of colours in cut and polished specimens, of which a pretty complete 
suite is added,) chiefly from the coast of Labrador and from the transi¬ 
tion syenite of Laurwig in Norway;—the adularia or naher feldspar, 
principally found on mount St. Gothard, but not in the valley of Adula 
from which its name is derived : the fine variety from Ceylon, when cut 
en ca6oc/mra, is called moon-stone; anda} r ellownaker feldsparwith reddish 
dots has obtained the name of sun-stone, which is also sometimes given to 
the beautiful avanturino variety of common feldspar placed in this glass- 
case ; — ice-spar and sanidine or glassy feldspar, both nearly allied to com¬ 
mon feldspar ; albite or clean elandite, the finest, specimens of which are 
those from Dauphine and Siberia; an dpericline, united by some minera¬ 
logists with the preceding species, from St. Gothard, Tyrol, &c. ;—- 
anorthite from Vesuvius ;— oligoclase, also called natron-spodumen— 
together with some other species separated, perhaps unnecessarily, from 
common feldspar and cleavelandite. 
Other mineral substances temporarily placed with the preceding, are, 
the leucite or amphigene, chiefly from Vesuvius, in separate crystals of 
various sizes and degrees of transparency, massive, embedded in pyroxe¬ 
nic and other lavas ;—the triphane or spodumen and petalite: in which 
latter substance lithia, or the oxide of lithium, was first discovered by 
Arfvedson ;—the nepheline , from Mount Vesuvius, with which are now 
combined the davyne of Monticelli and several varieties of the elceolite or 
D 3 
