CONTRIBUTIONS FROM THE HARVARD MINERALOGICAL 



MUSEUM.— XI. 



A DESCRIPTION OF EPIDOTE CRYSTALS FROM 



ALASKA. 



By Charles Palache. 



Presented by John E. Wolff, January 8, 1902. Received February 7, 1902. 



The epidote crystals described in this paper were sent to the Harvard 

 Mineralogical Laboratory for crystallographic study by Mr. W. C. Hart 

 of Manitou, Colorado, to whom we wish to express our thanks for the 

 generous supply of material placed at our disposal. 



This material is from a new locality for the mineral and is remarkable 

 for the size and unusual habit of the crystals ; it therefore seemed well 

 worthy of description. 



According to Mr. Hart the epidote is found at Sulzer, Prince of Wales 

 Island, Alaska. It is in the close vicinity of a body of copper ore and is 

 further associated with garnet, albite, magnetite, and quartz. The coun- 

 try rock of the region is limestone, which is cut by numerous igneous 

 dykes, and it seems probable that the deposit is the result of contact 

 metamorphism of the limestone by -the dyke rocks, resembling closely in 

 this respect the epidote occurrence with copper ore in the Seven Devils 

 Mts. in Idaho.* 



The specimens at hand consist of several loose crystals and a mag- 

 nificent cluster of large crystals implanted on massive epidote. The oi^ly 

 associated mineral is quartz in small clear crystals of later formation 

 than the epidote. 



The epidote is very dark green to greenish black in color, but oil- 

 green and translucent in thin crystals or where bruised or cracked. The 

 larger crystals are in the form of nearly square tables, which measure as 

 much as 5.5 cm. each way and 3 cm. in thickness. In the smaller crystals 

 the tabular habit is less pronounced and the mineral sometimes assumes 

 the ordinary prismatic habit parallel to the b axis. The crystals are not 



* Compare Am. J. Science, VIII, 1899, 299. 



