106 CORUNDUM, TTS OCCURRENCE AND DTSTRTBUTTON. 
Yellowish and blue colors in the same specimen are rather common 
and are sometimes sharply separated into consecutive bands, while ii 
other specimens the colors merge into one another. 
Sapphire gems of all the different colors have been found at Corun 
dum Hill, and I have in my collection cut gems representing all these 
various colors. Many of them are, however, very small. 
During the last fourteen years but few gems have been obtainec 
from this mine, for the reason that the portion of the deposit fron 
which these crystals were formerly obtained has not been worked. Ii 
the alluvial deposits below this portion of the mine many handsouK 
crystals can be obtained by washing the gravel. 
The green sapphire, which -is the oriental emerald, is one of the 
rarest of gems. The Corundum Hill mine is the only place in thi; 
country at which the emerald-green sapphire has been foiuid, and i 
occurs very sparingly here, although the yellowish and light-greei 
varieties are not uncommon. What is probably the finest knowi 
specimen of oriental emerald in the world came from this mine and i: 
now in the Bement collection. It is a crystal 4 by 2 by 1 J inches ; par 
of it is transparent, and several very fine gems could be cut from it 
At the Sapphire and Whitewater corundum mines, near Sapphire 
Jackson County, N. C, fragments of sapphire of a fine blue color havr 
been found, from which small but good gems have been cut. 
Associated with the green amphibolite rock near Elf post-office 
Clay County, N. C., deep-blue sapphires have been sparingly found 
These bear the same relation to the amphibolite as the red and pinl 
sapphire described on page 104. 
MONTANA. 
MISSOURI RIVER. 
Systematic mining for sapphires in the United States has beei 
undertaken only in Montana. Sapphires were first found in thi 
State by miners who were washing the gravels of the bars on the Mis 
souri River, east of Helena, for gold. These were first described ii 
1878 by Dr. J. Law^rence Smith,« but it w^as not until 1891 that actua 
mining Avas begun. During that year a number of companies wer 
organized to work these bars for sapphires. 
These bars are located from 12 to 18 miles east and northeast o 
Helena, and have been followed for a distance of about 12 miles fron 
Canyon Ferry down the river to American Bar. At various interval 
the bars have been worked for the sapphires and are designated \r 
the following names, starting with the one that is farthest up th 
« Am. Jour. Sci., 3(1 ser., vol. G, 1873, p. 185. 
