162 TRANSACTIONS OF THE [APR. 8, 
The feldspars appear in several of their choice varieties,— 
amazon-stone, moonstone, peristerite, etc., and in their amor- 
phous forms, as porphyry and obsidian. The use of all these 
materials for ornamental work is well illustrated, and indicates 
the possibility of much more extended application. The same 
remark applies to a number of other species of minerals which 
we are not in the habit of associating with use in jewelry or the 
arts. Among these may be mentioned the following: 
Wollastonite, diopside, scapolite, gadolinite, danburite, so- 
dalite, pectolite, schorlomite, etc. 
Two cut gems of canary-yellow willemite are worthy of par- 
ticular mention. 
The semi-precious stones, rhodonite, cyanite, chlorastrolite, 
and others, are of course represented. Very beautiful polished 
serpentines (Williamsite and Bowenite) are included; asalso the 
cut and polished fossil corals from the Devonian limestones of 
Iowa. 
Turquoise, from the New Mexican mines at Los Cerillos, is 
well represented, and possesses interest from the great value 
attached to it by the aboriginal races. This is doubtless the 
precious green stone so prized by the Aztecs under the name of 
chalchihuitl. Several of the specimens in this collection are 
native Indian work,—beads, charms, etc. 
Here may be mentioned a number of arrow-heads of obsidian, 
agate, chalcedony, silicified wood, hyaline quartz, citrine, etc., 
which show much taste in the selection of choice material, as 
well as delicate skill of execution, to have been possessed by the 
Indian tribes. 
Amber is represented by several specimens, among which the 
most striking is the Mexican piece previously described, with its 
green fluorescence. 
The last feature in the collection is the illustration of North 
American pearls and pearl-yielding shellfish. Green pearls and 
nacreous concretions from Haliotis (‘‘abalone”’) shells, of the 
coast of Lower California, and pink pearls from the West Indian 
conch (Strombus gigas), together with the clam and oyster 
pearls, black or white, of our own neighboring shore, are in- 
cluded; but the chief display of pearls proper is from the fresh- 
