398 SYSTEMATIC DESCUIPTION OF PRECIOUS STONES 



appears, however, that it was green and not blue turquoise which was held in such peculiar 

 esteem. The green precious stone chakhihuitl, so much esteemed by this ancient people, is 

 ■considered by some authorities to be identical with green turquoise ; others, however, suppose 

 it to have been emerald, jade, green jasper, or some other green mineral. 



After the fall of the Kingdom of Mexico the turquoise still continued to be the favourite 

 stone of the inhabitants of the region, that is to say, of the Pueblo and Navajo Indians. 

 W. P. Blake states that the stone is known to these people as chal-che-we-te, which is 

 supposed to be a corruption of the old name chalchihuitl. So greatly was the stone prized by 

 these Indians that only with the greatest difficulty could they he induced to part with their 

 turquoise-decorated tools and implements to white men. Such objects, moreover, were 

 •almost always buried with the dead, as recent excavations in the Indian burial-grounds of 

 that region have shown. 



The best known of the ancient turquoise mines is situated on the mountain named 

 after this stone, Mount Chalchihuitl (or Mount Chalchuitl) ; this mine was the first to be 

 rediscovered and was found by William P. Blake in the ''fifties. Mount Chalchihuitl forms 

 part of the conical mountain group Los Cerillos, about twenty-two miles south of Santa Fe, 

 the capital of the State of New Mexico ; it is situated on the northern bank of the Galisteo 

 river, which flows westward into the Rio Grande and separates the Los Cerillos district from 

 Ihe important mining district of the Placer or Gold Mountains. 



This mountain gi'oup, and in particular the turquoise-bearing Mount Chalchihuitl, 

 ■consists of sandstone, probably of Carboniferous age, intersected by dykes of augite-andesites. 

 These andesites, and the volcanic tuffs with which they are associated, contain in various parts 

 ■of the mountains ores of lead, copper, silver, and gold in no inconsiderable amount. They 

 are usually much decomposed and completely bleached by the action of volcanic gases and 

 vapours. The alteration and weathering of the rocks of this range has resulted in the 

 formation of new minerals of various kinds. Thus by the alteration of the felspar in the 

 volcanic rocks kaolin is formed ; from this mineral the turquoise, subsequently formed, 

 ■derives its alumina, the phosphoric acid being derived from the apatite in the same rocks, 

 ■and the copper, to which the colour of the stone is due, from the copper ores also embedded 

 in these rocks. All the turquoise appears to have originated in this way, the formation of 

 turquoise always following that of kaolin. The mineral is found here as elsewhere in small 

 nodules and thin veins, with a mammillated or botryoidal surface, in the andesite or 

 andesitic tuff, which is altered to a whitish or yellowish clayey mass. The turquoise is so 

 generally distributed through the rock that patches of it may be seen almost everywhere on 

 the walls of the mine. 



One of the ancient Mexican mines, which was without doubt worked before the 

 ■discovery of America by Europeans, has been described by W. P. Blake as an enormous 

 funnel-shaped pit, the sides of which are steep and precipitous. At one place there are 

 even overhanging rocks forming a kind of cave, while at another the slopes are more 

 gentle, owing to the falling in of waste material from above. An idea of the great age of 

 this artificial excavation may be derived from the fact that on its sides are growing pines, 

 ■cedars, and other trees hundreds of years old. It is about 200 feet deep and 300 feet wide, 

 ■and out of it many thousands of tons of solid rock must have been excavated. In its 

 neighbourhood are to be seen similar but smaller pits, and it would seem that the whole 

 surface of the turquoise-bearing mountain was turned over in the search for the precious 

 stone. Beside these surface-workings there exist also underground mines excavated at the 

 same time, some of which are of no inconsiderable extent. These were discovered when 

 a,ttempts were made to rework this old deposit ; and in the old mines were found relics of 



