105 



the "West. Specimeus of ricli wash-dirt, travertine false-bottom, 

 bed-rock showing gold, pug, and associated minerals are 

 exhibited. 



A few specimens from New Guinea, Borneo, and New Cale- Case 79. 



donia. East Indies, 



&c. 

 1C028, Celebes ; a quartz geode (occurring in limestone), 



with platy gold on the quartz. 



10027, Celebes ; veins of auriferous quartz in porphyry. 



10026, Sumatra. 



A typical series of auriferous quartz from the working mines of United States. 

 California. Also ores from Oregon, Dakota, "Washington, Vir- 

 ginia, Mercur, and elsewhere. 



The telluride ores of Cripple Creek, Colorado, will be of 

 interest : — 



9189 ; a volcanic rock, andesite, showing a joint-face coated 

 M'ithjluor and sylvanite (telluride of gold and silver). 



9191 ; a very common brecciated form. 



6467; with purple ^Mo;\ The presence of fluor is regarded 

 as an indication of gold. 



*8618 ; i-oz. ore, containing purple fluor and antimonite. 

 Yarious other ores with assay values up to 50 oz. per ton are 

 shown. 



*8624 ; oxidized ore, showing the peculiar clay-like variety of 

 gold (see page lOi) which appears to be characteristic of the 

 oxidation of telluride ores. 



*8619, 8628, are of exceptional interest. Each specimen shows 

 crystals of telluride of gold from which the tellurium has partly 

 been removed, probably by volatilization, the gold remaining as 

 a pseudomorph. 



9190 ; average rich ore ; 4-oz. stone. 



In case 92 (see page 125) will be found picked specimens of 

 gold-telluride minerals from Colorado. 



* These specimens are in case 92. 



