154 W. T. Schaller — Mineralogical Notes. 



nearly equal amounts. These relations can also be shown by 

 the folio wins: table: 



Purpurite from Fe.,0 3 .P 2 5 .HoO. 



Mn a 3 .P a O s .H a O. 



South Carolina contains (approx.) 35 per cent 



65 per cent 



Connecticut " " 53 " 



47 



South Dakota " " 76 



24 " 



Should the two end products be found at some future time, it 

 would not be inappropriate to designate them as ferripurpurite 

 and manganipurpurite, retaining the name purpurite for either 

 the isomorphous mixture of the two end products or else for 

 the whole group, in a way similar to that in which the terms 

 garnet or mica are now used. 



2. Manganotantalite from Mi. Apatite, Maine. 



The crystals here described were received from Prof. C. 

 Palache, who suggested they were manganotantalite. They are 

 associated with the minerals so characteristic of these lithium- 

 bearing pegmatites, as albite, lepidolite, etc. The crystals are 

 mostly small, several millimeters in length, and are usually tabular 

 to the a face (Dana's orientation). A specific gravity determi- 

 nation gave a value of 7*14, showing that in these crystals the 

 tantalic acid largely predominates over the columbic acid. A 

 partial analysis further showed that iron was almost entirely 

 absent, so that the crystals may well be termed manganotantalite. 

 The analysis gave the following results : 

 Ta„6. 



Cb o 6 r " 85 ' ? ° 



FeO... -16 



MnO... 14-49 (by diff.) 



100-00 

 The forms present are: b= {010}, a= {100], c— {001],, 

 m={llO],g={l30},j*={320},z=={m\ d= {730], k= {103], 

 u= {133], n— {163]. The angles measured are shown be- 

 low. Most of the faces were dull and gave poor reflections. 



Measured. Calculated. 



50° 28' 50° 22' 



21 27 21 55 

 63 10 63 34 

 70 15, 70° 06' 70 27 

 19 38 19 42 

 30 approx. 30 50 



118 approx. 118 20 



22 approx. 19 54 

 50 45 50 03 

 81 15 79 54 

 30 04 29 57 







/\ 



m 



= 



010 : 



: 110 



b 



/\ 



g 



= 



010 : 



: 130 



b 



/\ 



z 



= 



010 : 



: 530 



b 



/\ 



d 



= 



010 : 



: 730 



c 



/\ 



h 



= 



001 : 



: 103 



b 



y\ 



n 



= 



010 



: 163 



n 



/\ 



n"' 



= 



163 



: 163 



n 



y\ 



n' 



= 



163 : 



: 163 



b 



y\ 



u 



:=z 



010 : 



: 133 



u 



/N 



u" 



/ 



133 



: 133 



u 



/s 



u' 



= 



133 



: 133 



