19 
ing, is occupied by calcedonic substances. Among saloon. 
the specimens of common calcedony the most re- Nat. Hist. 
markable are the smalt-blue variety from Felso- 
banya in Transylvania, crystallized in cubes; 
the branched and stalactical calcedony from Tre- 
vascus in Cornwall, from Iceland, &c. the bo- 
tryoidal from Ferroe ; nodules including water 
(enhvdrites) from Monte Berico, near Vicenza, 
where they are said to occur in volcanic rocks ; 
cut and polished pieces of calcedony, with black 
and red dendritic and other figures, vulgarly 
called mocha stones ; varieties with white, brown 
and black, straight or curved lines : onyx, sard¬ 
onyx, &c. 
(Case 7.) Calcedonic substances continued: 
among these are various specimens of the red 
and yellowish varieties of calcedony, called car- 
nelian; striped carnelians, &c.—Heliotrope, an 
intimate mixture of calcedony and green earth, 
which, when containing disseminated particles 
of red jasper, is commonly termed blood stone* 
—The beautiful and much esteemed variety of 
calcedony, called chrysoprase: it has hitherto 
been only found at Kosemiitz in Silesia, accom¬ 
panied by a siliceous earthy substance, called 
pimelite, which, like the chrysoprase, owes its 
green colour to oxide of nickel.—By way of ap¬ 
pendix to the calcedonic substances, are added a 
1 2 few 
