MINERALOGICAL NOTES: No. III.— AXINITE, 

 PETTERDITE, CROCOITE, and DATOLITE. 



By C. AxDERSox, M.A., B.8c., Mineralogist. 



(Plates xxix. — xxxiii. ). 



AXINITE. 



BowLiNt; Alley Point, near Nundle, New .South Wales. 



(Plate xxix.). 



Axinite was first found at this locality by Mr. D. A. Porter,' 

 to whom I am indebted for notes as to its mode of occurrence. 

 The exact location is about a ((uarter of a mile from the foot- 

 bridge over the Peel River, where the mineral is found associated 

 with green epidote in sedimentary rocks much altered by intrusi\e 

 diorite : it occurs sometimes in crystalline \'eins, but the best 

 specimens are obtained in cavities, where the crystals have grown 

 freelv, accompanied by small well-formed quartz prisms. Good 

 crystals are rare and minute ; larger, more imperfect ones can be 

 found measuring up to 15 mm. The colour is l)rownish with a 

 \ iolet tinge on a fresh fracture. 



Three of the best crystals, each measuring about ■? mm., were 

 r(^mo\ed from tlie matrix, and their faces determined on a two- 

 circle goniometer ; owing to their mode of attachment the crystals, 

 were fractured in removal along a line roughl}' parallel to the 

 edge I) ■>• (PI. xxix., figs, o, 4). After several trials the habit was 

 made out, but it was found impracticable owing to tiie small size 

 and unsatisfactory nature of the prism faces to centre the cry.stals 

 in the conventional position ; instead, the most prominent zone — 

 either [010, 111] or [130, 021] — was made equatorial and the 

 available angles determined, after which the crystal was inverted, 

 and, with tlie same zone as before equatorial, the angles yielded 

 by the faces on the other end measured. By plotting the co- 

 ordinates in stereographic projection, the forms were easily 

 identified by the aid of PenfieUl's invaluable protractors. From 

 the measurements, the normal angles were calculated for com- 

 parison with the theoretical values calculated from (>oldschmidt"s 

 " Winkeltabellen."- Tiiis method, though it docs not afford 

 direct comparison of measured with calculated angles, is sufficient 

 to prove the correctness of identification. 



In liabit the crystals are uniformly tabular on /• (111), whicli 



1 Liversidge Journ. Rov. Soc. N.S. Wales, xviii., IH84 (l.SS.j), p. 45; 



Porter Thirl., xxii.." 18HK (1H89), j). 82. 

 - GolcWliiiii.lt IvrvstallouTMi.liisclic VViiikcltiilH'lKii. ls<7, ... .".S. 



