FORM SYSTEM OF THE WOLFRAMITE GROUP. 71 



>1{T01}, described first by Groth and Arzruni and later noted by 

 ( i roth, (but without measurement), is also doubtful. (001) : (T01)~ 

 48 37' measured and 46 38' calculated, the difference being 1 59'. 



2(113} given by Miller * has always been considered a questionable 

 form. Though inserted by Goldschmidt in his Winkeltabellen with 

 a query, it had best be omitted. The symbol may be a misprint 

 for {112}. 



Eakle gives the letter v to a new form {T22} on wolframite from 

 Nevada, but as the letter v is already preempted by the form {552}, 

 Eakle's letter is changed to V. Eakle's letter Ji should be changed 

 to d and d changed to e. 



It may be noted, too, that the correctness of the positive or nega- 

 tive character of several of the forms listed is very questionable. 

 This is particularly true of the domes described by Krenner, who 

 himself called attention to this uncertainty. 



Figure 35 shows the gnomonic projection of all the known forms of 

 the wolframite series except r{321}, which falls outside of the projec- 

 tion, and ;r{754}, which was described after the gnomonic projection 

 was drawn and reproduced. The position of the forms is indicated 

 in figure 35 by dots, whereas the position of some of the forms in twin 

 position (twinned on {023}) is shown by open circles. 



All the forms lie in well-developed zones. The prism zone is the 

 richest, containing a total of 17 forms, but hardly any of the simple 

 zones are poor in forms. 



The position of many of the twinned forms is nearly identical with 

 other forms which are not twinned and which are in their normal 

 position, as, for example, ^{102} and <r{121}, c{001} and w{02l], 

 {102} and s{T21}, s{T21} and t{W2}, <r{121} and y{T02}, ${121} 

 antU{T21}. 



FORMS AND COORDINATE ANGLES. 



The following table of forms and coordinate angles shows several 

 points to which attention may be called. If a form is considered 

 doubtful that is, if it seems uncertain whether such a form actually 

 exists the question mark used to indicate this is placed with and 

 immediately following the letter of the form. Thus w ?{021} means 

 that there is doubt as to whether such a form has actually been found. 

 If, on the other hand, there is no question about the existence of the 

 form, but the symbols seem to be incorrectly determined, or at least 

 a verification of the correctness of the measurement is desired, the 

 question mark is placed after the symbols, thus {7.11.0} ?. 



References are given when the form has been seen and described 

 by only one observer or two independent observers. If at least three 

 different observers have noted the form its confirmation would seem 



i Mfller, W. H., Elementary introduction to mineralogy, p. 473, 1852. 



