U8 



RULIFF S. HOLWAY 



cles of free gold were found in the granular garnet. The rock has 

 attracted the attention of prospectors, and it is reported that an assay 

 showed nearly two dollars of gold per ton. In a few places there were 

 inclusions, some 10-15"'"'' '^^ diameter, of a reddish-brown mineral 

 with cleavage faces giving an almost metallic luster. In the labora- 

 tory the mineral was found to be infusible and to possess a hardness 



Fig. I. — Eclogite from San Martin, Calif. Slightly reduced in size. 



of over six. The streak is yellowish-brown. A determination of 

 the specific gravity of the purest fragment obtainable gave a result 

 of 4.154. After fusion with soda the acid solution boiled with tin 

 gives the violet reaction of titanium. The mineral was determined 

 as rutile — a result which the microscopic examination of a thin sec- 

 tion confirmed. 



The specific gravity of the eclogite itself varied from 3.33 to 3.58 in 

 different fragments — apparently varying with the number of garnets 

 included. Some of the garnets were separated from the groundmass 

 and found to have a specific gravity of 3.68. A c|uahtative determi- 



