128 DESCRIPTIONS OF MINERALS. 



This metal is malleable, and when polished has a Trhitish 

 steel-like lustre which does not tarnish. A cup weighing 

 3J pounds was made by M. Breant in the mint at Paris, and 

 is now in the garde-meubU of the French crown. In hard- 

 ness it 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 Koyal 

 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 Mercury, 



Isometric. Occurs in fluid globules scattered through the 

 gangue. Color tin-white. G-.— 13*56. Becomes solid and 

 crystallizes 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 is some- 

 times accumulated in cavities so as to be dipped up in 

 pails. 



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 SulpMde. 



Ehombohedral. EaR='7'2 36'. Cleavage lateral, high- 

 ly perfect. Crystals often tabular, or six-sided prisms. Also 

 massive ; sometimes in earthy coatings. 



