20 
saloon, mocha stones; varieties with white, brown, and 
Nat.Hist, black, straight or curved lines; onyx, sardo- 
* nyx, he. 
(Case 7.) Caicedonic substances continued. 
Among these are various specimens of the red and 
yellowish varieties of calcedony, called carnelian: 
striped carnelians, he.—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 calce¬ 
dony, called chrysoprase .* it has hitherto been 
only found at Kosemutz in Silesia, accompanied 
by a siliceous earthy substance called pimelite, 
which, like the chrysoprase, owes its green colour 
to oxide of nickel.—By way of appendix to the 
caicedonic substances, are added a few specimens 
of the less compound varieties of agates, in which 
common calcedony, carnelian, and heliotrope 
respectively form the predominant ingredients. 
(See also the table-cases, Room I.)— Otflint, a 
well known mineral substance, several interesting 
varieties are deposited in this case. 
(Case 8.) contains principally opaline sub¬ 
stances, viz. specimens of the noble opal, which 
owes its beautiful play of colours to a multiplicity 
of imperceptible fissures in its interior ; the Mexi¬ 
can sun or fire Gpal; the common opal, a translu¬ 
cent white variety of which, appearing yellow or 
red when held between the eye and the light, is 
called girasol ; the semi-opal , agreeing in its prin¬ 
cipal 
