402 Scientific Intelligence. 



No apatite could be seen in the trachyte and the writer suggests 

 that the phosphoric acid may have been derived from the adja- 

 cent limestone which is fossiliferous and which may have capped 

 this trachyte at no very distant day. 



As the turquoise is found in its natural position, it gives strong 

 evidence that the oxidation of the pyrite is the sole cause of the 

 decomposition of the trachyte, etc., the cause also of the forma- 

 tion of the limonite, gypsum and jarosite and is itself a product 

 formed subsequent to the kaolin. The kaolin is in one sense pri- 

 mary and the turquoise secondary, as its form and situation in the 

 vein, crevice or pocket always proved. That all the turquoise was 

 once kaolin was very evident. That the turquoise was the last 

 mineral formed and was crystallized or grew amid the kaolin and 

 was a gradual and direct alteration of it was positively shown in 

 many ways. The majority of the turquoise masses are semi-globu- 

 lar or reniform in outline though compact masses are found 

 wholly occupying small cavities and following exteriorly all the 

 configuration of the " pockets." At one time I uncovered a sur- 

 face of turquoise nodules nearly three feet square — some of it 

 three-fourths of an inch thick — and the edges of the masses and 

 nodules always terminated thickly and abruptly in the kaolin 

 with a rounded minute botryoidal surface. While the tendency 

 is towards blue in the Jarilla turquoise — more so than at any of 

 the other places herein noted — there also occurs (rarely) in the 

 surface veins, some very green varieties, some as green as chryso- 

 lyte rock. Any tendency towards green is an evidence of altera- 

 tion. 



Abundant as the turquoise is near the surface, it too, undergoes 

 decomposition and sooner or later becomes white, soft and pulver- 

 ulent. At depths below twenty-five feet the turquoise when first 

 found is of a magnificent, almost ethereal, tint of blue, but this 

 rapidly fades after it is detached from its matrix and becomes 

 dry. I have seen it as deep blue as indigo and then fade gradu- 

 ally to a " robin's egg " shade. If after drying, turquoise adheres 

 to the tongue it can be classed at once as of low grade and pos- 

 sessing little value. Where the rock is purest there the turquoise 

 is found of best color, normal hardness and greatest durability. 

 As the other " old workings " in the Jarillas become developed, it is 

 thought that they will disclose turquoise as hard, as beautiful and 

 as large, as the world has as yet seen. I state this advisedly from 

 the fact that some fifty kilos of marketable turquoise was shipped 

 from this locality in the first six months working and only one of 

 the prehistoric mines was developed. 



The Mexicans believe that both the "old Pueblos " and Aztecs 

 worked these mines and it is true to-day that the Pueblos value 

 turquoise — which they term "shooar-me" — even more than the 

 Navajoes. The Apaches call it " steh" and care little for it. The 

 Mexican name for it is " char-chu-a-tey," which calls to mind the 

 Aztec " chal-chi-hui-tl," of many authors. 



