C. H. Warren — Mineralogical Notes. 373 



The measured angles and their corresponding calculated 

 values are given beyond, the later being taken from the funda- 

 mentals established by Des Cloiseaux* for wolframite : 









Measured. 



Calculated. 



a ^ 



c 



== ]00 ^ 001 = 



89° 25' 



89° 21' 



m /s 



tri 



= 110 ^ 110 = 



100 19 



100 37 



m /s 



b 



= 110 ^ 010 = 



50 22 



50 18J 



I /s 



V 



— 210 /s 210 = 



134 45 



134 55£ 



i ^ 



i' 



— 7-11-0 /s^'11-0 = 



74 51 



74 59 



a ^ 



t 



= 100 ^ 102 = 



61 45 



61 54 



«'y\ 



y 



= 100 A 102 = 



63 8 



62 54 



a ^ 



f 



= 100 ^ 011 = 



89 35 



89 31 



m ss, 



A 



= 110 /s 112 — 



55 34 



55 28 



Considering the character of the faces the foregoing meas- 

 ured and calculated values show a satisfactory agreement. The 

 chief interest connected with this mineral is that it gives 

 almost no reaction for manganese, indicating that its composi- 

 tion is very nearly that of an iron tungstate, FeW0 4 . So far as 

 known to the writer, it is the first occurrence of a variety of 

 this mineral free from manganese, and it is to be hoped that 

 more may be learned of its place of occurrence. 



Pseudomorphs of Wolframite after Scheellte from Trumbull, Conn. 



Pseudomorphs of wolframite after scheelite have been 

 known for some time to occur at Trumbull, Conn., where they 

 are found in a highly siliceous vein associated with pyrite and 

 a little native bismuth. The pseudomorphs attain a consider- 

 able size, sometimes measuring 3or4 cm in diameter, and usually 

 present the habit of the simple 

 pyramid common to scheelite, p, 6 



111, often modified by the pyra- _<>*?■■ g__>^^^ 



mid of the second order <?, 101. / / \ — ~ \^ _\\ 



The accompanying figure repre- A^T 7 ^ loV^J^/ 



sents a somewhat more compli- \£±> — -v \Y J 



cated habit and was drawn from \f . - : \"_ ''""_ )J^r 

 a fine crystal kindly loaned by Mr. ^ s^ 



Lazard Calm of New York. The 



most prominent form is 0, 101, truncated by 0, 102, and termi- 

 nated by a basal plane c. The corners are modified by pyra- 

 mids, of the first order p, 111, and of the third order s, 131. 

 The angles of the crystal measured with a contact goniometer 

 show a satisfactory agreement with the corresponding angles 

 given for scheelite. A number of crystals showed, on break- 

 ing, a light colored core of scheelite still remaining within the 

 black exterior of wolframite. 



*Am. Ch. Phys., xix, 168, 1870. 



