62 



California Art & Nature 



63 



Gulf of Cortes, in Baja California. • I 

 have found small fragments in San 

 Diego county, evidently brought from 

 a distance by the Indians, who valued 

 volcanic glass for the manufacture of 

 arrow and spear points. 



OPAL — Occurs on the Colorado des- 

 ert, and also credited to the limits of 

 the city of San Diego, but only the in- 

 ferior varieties are yet known in Cali- 

 fornia. Banded opal has been describ- 

 ed as occurring in Beaver valley, Utah, 

 some three miles from Granite Peak. 

 See hyalite. 



PECTOLITE— "A silicate of alumi- 

 num, calcium, and nat lum." Has bed 

 reported as occurring in Southern Cal- 

 ifornia. 



PERIDOT— New Mexico. 



PLATINUM— This metal is found on- 

 ly in metalic condition, sometimes al- 

 loyed with iridium or osmium. A nug- 

 get weighing nearly two pounds (only 

 2%x3 inches in size) from Colombia, 

 South America, kas been reported as 

 the largest in America, with an in- 

 trinsic value of $350. It contained 85 

 per cent pure platinum and 15 per 

 cent of gold, palladium and rhodium, 

 and had a bluish-white lustre. This 

 metal is almost as soft as copper and as 

 ductile as gold. It can be rolled so 

 thin that a thousand sheets in a pile 

 would not exceed an inch in height. 



PLUMBAGO— See graphite. 



PREHNITE— San Ysldro, Ba;a Cali- 

 fornia, associated with calcite. 



QUARTZ— A cubic foot weighs 162 

 pounds, 12.34 cubic feet making a ton. 

 Occurs in an endless number of varie- 

 ties. See agate, carnelian, chalc^dony, 

 has been found by the writer near 

 jasper, etc. 

 Mesa Grande. 



Silicified wood occurs in various 

 parts of San Diego county, but in the 

 greatest abundance and variety on the 



Rose quartz in magnificent masses 

 Colorado desert; while Arizona is no ;ei 

 for its Chalcedony park, where an en- 

 tire forest is preserved in a beautiful 

 agatized form. 



Diatomaceous earth occurs on the sea 

 coast near San Diego. 



RHODONITE— "Between San Diego 

 and Colton." 



RUTILE — This rare mineral was dis - 

 covered by the writer at Mesa Grande 



SALT— See halite. 



TALC — A foliated variety occurs at 

 Elsinore, Cal. See antcnite. 



TOURMALINE— See achroite, Brazil- 

 ian emerald, indicolite, rubellite and 

 schorl. 



The remarkable deposit at Mesa 

 Grande, which developed in ISOO many 

 fine t;-an^luc?nt, or even transparent, 

 large, separate crystals with perfect 

 prisms and terminations has not failed 

 to arouse the cupiuity of man — as has 

 frequently been the case with discover- 

 ies of gems. Litigation has therefore 

 att.nied iti further deve:opmeat this 

 year, but ISOl has seen it produce from 

 $25,0i;0 to $120,000 cr more in gems and 

 precious stones — according to the var< 

 ious reports that have been circulated— 

 only a small part (as u;ual) goi g to 

 those who proved its vaue. The gan- 

 gue cf Mesa Grande tourmaline is gen. 

 era ly wl.i e. opaque quartzite, thb 

 crystals penetrating it in all directions. 

 Some cour in lepidolite which occurs 

 in larger and more brilliant sc les than 

 in tni wel -known locality at Pa a. 

 Owing to the great variety cf co or ng, 

 si^e, lere tion aid beatty, this iocaU 

 ity has proved the most important yet 

 fou- d in the United Spates if not in trie 



The objects of this association are lo 

 further the systematic and scienti c 

 exploration of West America, and to 

 foster and promote in every l3gtmr.t? 

 manner the various branches of t" e 

 mineral industries. Thece are hin- 

 drcds of unievelooed mne eI p- p - 

 ties in the wesLern United States and 

 Mexico, containing goid, silver, co.ter, 

 iron, lead, and other metals, or valu- 

 able minerals, waiting for some one 

 with capital and business judgment to 

 turn them into paying mines. No in- 

 vestment yields better returns than a 

 good mine. But there are thousands 

 of alleged mines or prospects, and 

 many fortunes have been spent on 

 worthless claims, whil3 valuable p o - 

 erties are often ignored for years, until 

 chance or education reveals their val- 

 ue. 



TURQUOISE — Reported from the 

 Colorado desert, but no specimens have 

 as yet been seen by the writer. Cer- 

 tain copper ores are easily mistaken 

 for this stone. Mines of this g?m --f 

 great extent are being worked in the 

 Mojave desert region northwest cf 

 Vanderbilt. 



