SOUTHERN CALIFORNIA ACADEMY OF SCIENCES — 85 
GEMS AND RARE MINERALS OF SOUTHERN 
CALIFORNIA. 
By L. Douglas Sovereign. 
(Read before Section of Geology, April 24, 1905.) 
Hidden deep in the heart of the heat distorted Colorado 
Desert, in San Diego County, guarded by great inaked buttes 
that frown down upon the intrepid prospector, is probably one 
of the richest of Nature’s unrifled coffers of crystalline wealth. 
This little southwestern corner of the country, embracing 
the desert waste and the low mountain range between it and 
the sea, might well be named the jewel casket of the United 
States. : 
Though as yet only the hardiest of prospectors have ventured 
from the beaten trails that mark the shortest route from water- 
hole to water-hole, those who have dared have either left their 
bones to whiten on the arid plain or been rewarded by evidence 
of vast undeveloped wealth. 
Where the prospector’s pick has uncovered those closely 
guarded secrets in this remarkable section, finds of commercial 
importance and of great scientific interest have been rec- 
orded. 
There is probably no known section in the world that today 
offers the gem hunter greater possibilities, and there are few 
fields offering the geologist greater reward for research. 
The astonishing discovery of rare minerals and unsurpassed 
crystals in the dwarf mountains to the west have comparatively 
recently brought this section into prominence. The finding of 
the richest and most productive known deposit of tourmaline 
erystals, the uncovering of the only known deposit of lilae- 
colored spodumene and the discovery and development of lepi- 
dolite in quantities never dreamed of before the uncovering of 
the Pala dike, are among its claims to distinction. 
In importance the discovery of the lepidolite deposit, where 
development has brought to light immense quantities of ores of 
lithia, estimated by the thousands of tons, probably ranks 
first. The locality, without doubt, is unequaled in the world 
for its abundance of lithia minerals, as the deposit contains, 
besides high grade lepidolite ore, immense quantities of ambly- 
gonite. 
The Pala mines would be interesting from almost any point 
of view. To the scientist the geology of the great dike of 
hthium bearing muscovite, tracked for hundreds of feet by 
well defined croppings, affords a study worthy of his best ef- 
forts. Commercially this deposit is of importance. Its prin- 
