598 WELLS AND BUTLER: TUNGSTENITE, A NEW MINERAL 



abundant small somewhat rounded grains of pyrite could be 

 detected in it. A polished section revealed a little galena also. 

 The analysis indicates tennantite and tetrahedrite, which were 

 not distinguished in the single polished section of the material 

 examined. A portion of the polished section which had a slight- 

 ly bluish tinge was identified by microscopic reaction as tung- 

 stenite. The tungstenite is so soft that it wears away much 

 faster than pyrite during polishing. The hardness appears to be 

 about 2.5. Particles which are very easily cut from the massive 

 piece with a knifeblade appear under the microscope to consist 

 of feathery leaves or flakes resembling graphite. The mineral 

 is opaque. It marks paper, soils the fingers slightly, and rubs 

 up between a mortar and pestle like graphite. The cleavage 

 and fracture could not be determined. The luster varies from 

 dull to brilliant metallic; the color is dark lead gray; and the 

 streak is dark gray. The actual specific gravity of the second 

 specimen mentioned was 6.43. Allowing as well as possible for 

 the impurities and undetermined material, the specific gravity 

 of the tungstenite is calculated to be about 7.4. This may be 

 compared with the following specific gravities, MoS 2 4.7, FeS 2 

 4.9, Mo0 3 4.5, W0 3 6.3. 



Tungstenite appears to be unattacked by hydrochloric acid 

 or nitric acid. It is decomposed by aqua regia or by fusion with 

 sodium nitrate. Its behavior in a bulb tube and on charcoal 

 can not be stated definitely because of the impurities, though it 

 appears to be a rather stable compound, not even being oxidized, 

 by roasting in air. It burns with incandescence in oxygen. 



Tungsten was determined by decomposing the ore with aqua 

 regia. The solution was evaporated to dryness and the insolu- 

 ble material taken up in dilute hydrochloric acid and filtered off. 

 After extracting it with ammonium acetate to remove any lead 

 sulphate present it was heated with ammonium hydroxide. A few 

 per cent of residue remained insoluble in ammonia and con- 

 tained some tungstic oxide, a little silica, some iron, and other ma- 

 terial not yet determined. The filtered ammoniacal solution was 

 evaporated to dryness and the residue was ignited and weighed 

 as tungstic oxide. The other constituents were determined 

 as in the analysis of tetrahedrite, after decomposing a portion of 



