128 DESCRIPTIONS OF MINERALS. 
This metal is malleable, and when polished has a whitish 
steel-like lustre which does not tarnish. A cup weighing 
31 pounds was made by M. Breant in the mint at Paris, and 
is now in the garde-meuble of the French. crown. In hard- 
hess 1t is equal to fine steel. 1 part fused with 6 of gold 
forms a white alloy ; and this compound was employed, at 
the suggestion of Dr. Wollaston, for the graduated part of 
the mural circle constructed by Troughton for the Royal 
Observatory at Greenwich. Palladium has been employed 
also for certain surgical instruments. 
MERCURY. 
Mercury occurs native; alloyed with silver forming na- 
tive amalgam; and in combination with sulphur, selenium, 
chlorine, or iodine, and with sulphur and antimony in some 
tetrahedrite. Its ores are completely volatile, excepting 
when silver or copper is present. 
Native IMfercury, 
Isometric. Occurs in fluid globules scattered through the 
ganeue. Color tin-white. G.=13°:56. Becomes solid and 
erystallizes at a temperature of —39° F. 
Mercury, or quicksilver, as it is often called (a translation 
of the old name ‘‘argentum vivum),” is entirely volatile 
before the blowpipe, and dissolves readily in nitric acid. 
Obs. Native mercury is a rare mineral, yet is met with 
at the different mines of this metal, at Almaden in Spain, 
Idria in Carniola (Austria), in Hungary, Peru, and in Cali- 
fornia. It is usually in disseminated globules, but 1s some- 
times accumulated in cavities so as to be dipped up in 
ails. 
Mercury is used for the extraction of gold and silver ores. 
It is also employed for silvering mirrors, for thermometers 
and barometers, and for various purposes connected with 
medicine and the arts. 
Native Amalgam. See page 117. 
Cinnabar.—Mercury Sulphide. 
Rhombohedral. RA R=72° 36’. Cleavage lateral, high- 
ly perfect. Crystals often tabular, or six-sided prisms. Also 
massive ; sometimes in earthy coatings. 
