natural history. (Minerals.) 
71 
GALLERY.] 
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 chemical analysis has as yet been given of it: 
(among the vessels wrought out of Chinese jade in this Case is a cup, 
the gift of the king of Ava to the late Lieut.-Col. Burney, when British 
Resident at that court, and by him presented to the British Museum ;) 
—some varieties of nephrite appear, from external characters, to be 
nearly related to this substance. In this Case also is placed the har- 
motome or cross stone, (formerly called andreolite , alter Andreasberg, in 
the Hartz, w r here it was first discovered,) divided into baryte-harmotome 
and lime- or potassa-harmotome, to which latter are to be referred the 
Vesuvian minerals called zeagonite , gismondine , or abrazite , and the 
philipsite. ( Of andreolite, a magnificent specimen is deposited, pre¬ 
sented by King George IV.)—the herschelite, from Aei Reale in Sicily. 
—The remaining space in this Case and the greater part of 
Cases 30 and 31 are occupied chiefly by feldspathic substances and 
minerals more or less nearly related to feldspar. The most remarkable 
and important species is the common feldspar ( orthoclase of Breithaupt), 
among the crystallized varieties of which may be particularized—the 
fine green variety from the Ural, called amazon stone ; the suites of 
varously modified crystals from Baveno in Piedmont, from lake Ilmen 
in the Ural, and from Somnitz, &c., in Silesia; feldspar with em¬ 
bedded crystals and fragments of quartz (graphic stone, graphic gra¬ 
nite), from Siberia, &c.;—the adularia or naker 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 
cabochon, is called moon-stone ; and a yellow naker feldspar with 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 
orthoclase;—the albite or cleavelandite , the finest specimens of which 
are those from Dauphine and Siberia; the pericline, united by some 
mineralogists with the preceding species, from St. Gothard, Tyrol, 
&c. ;—the anorthite from Vesuvius;—the oligoclase, also called natron- 
spodumen, to tvhich may be referred the crystals occurring in several 
varieties of porphyry;—the labradorite 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 transition syenite 
of Laurwig in Norway * ;—together with some other species separated 
from orthoclase. To these is added the leucite or amphigene, chiefly 
from Vesuvius, in separate crystals of various sizes and degrees of 
transparency, massive, embedded in pyroxenic and other lavas. 
Case 31. Among other mineral substances here deposited, and 
partly belonging to the preceding section, are, the triphane or spodu- 
men and the petalite: in which latter substance lithia was first dis¬ 
covered by Arfvedson;—the davyne of Monticelli;—the nepheline , 
from Mount Vesuvius, with which are now combined several varieties 
* The top of the small octagonal table, standing near Case30,is a slab of opales¬ 
cent feldspar from Finland. 
