PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. fif) 



had assays of 300 ounces in silver from the mineral. I have also noted large 

 flakes of molybdenite associated with it, but all that was ever mined has been 

 carried away. 



I note that you have only a few fragments of the mineral left so I am sending 

 my specimen, which is the finest I have yet seen. I hope to get more. I am 

 sending also all the other minerals associated with it, including three or four colors 

 of material that leach out of the ledge, also a small piece of the soda granite. 

 Close to this Outlaw tunnel is a deposit of cinnabar with values in free gold. 



Three miles east on the same contact is another bismuth-silver deposit, the 

 bismuth here being in the form of carbonate. Three miles west is a deposit of 

 the molybdenite like the sample sent. 



ASSOCIATED MINERALS. 



The minerals occurring in the specimens with the benjaminite are 

 quartz, chalcopyrite, pyrite, covellite, muscovite, molybdenite, and 

 fluorite. 



The quartz is coarsely crystalline white vein quartz which forms 

 the gangue of the other minerals. As seen in thin section under the 



Quart, 



^o1^t><l«Tilt. 



FiQ. 1.— Sketch of Polished Surface of Benjaminite Showing Relation of Benjaminite to 



Quartz and Chalcopyrite and Replacement of Chalcopyrite and Benjaminite by Covellite. 

 FiQ. 2.— Sketch of Polished Surface Showing Relations of Benjaminite, Molybdenite 



Chalcopyrite, and Quartz. 



microscope it forms broad interlocking crystals which contain 

 numerous fluid inclusions which are visible with the higher powers 

 of the microscope. Some of the largest of these contain bubbles 

 and the smaller are aligned into strings. A later introduction of 

 quartz took place filling numerous very fine fractures in the older 

 quartz, and especially in the sulphides. These later quartz seams 

 are especially conspicuous in polished surfaces of the sulphides under 

 the microscope and are indicated in the drawing (fig. 2). 



Muscovite is common in the quartz as scales and aggregates of 

 scales. The individual crystals range up to 1 cm. in diameter and 

 are in part hexagonal in outline. In color the mica varies from pale 



