CONTRIBUTIONS FROM THE HARVARD MINERALOGICAL 



MUSEUM.— X. 



APATITE FROM MINOT, MAINE. 

 By John E. Wolff and Charles Palaciie. 



Presented December 11, 1901. Received February 7, 1902. 



In the summer of 1901, while prospecting for tourmaline or other 

 gem minerals on the farm of Mr. P. P. Pulsifer in Minot, Maine, a 

 pocket was opened in the granite containing the material here described. 

 It was first brought to our notice by Mr. C. L. Whittle, formerly of this 

 Department, and the whole was subsequently acquired by the Harvard 

 Mineralosrical Museum. 



This find is noteworthy for the unusually rich purple color of the 

 crystals, and the purity, crystalline perfection, and abundance of the 

 material, which comprises about two thousand loose crystals or frag- 

 ments of crystals with a total weight of over a kilogramme, and about 

 a dozen large groups of crystals on the matrix. Of the loose crystals 

 about three hundred show at least one perfect termination, five hundred 

 are slightly less perfect, and the rest imperfect or fragmentary. 



Paragenesis. 



The apatite was found in a single cavity in pegmatitic granite, the 

 walls of which appear to have been lined with crystals of quartz, ortho- 

 clase, and lepidolite, with which in smaller amounts were albite, musco- 

 vite, and cookeite. 



The quartz crystals range from small dimensions up to a height and 

 thickness of 15 cm. They show the common quartz forms only, the 

 positive and negative unit rhombohedrons and the prism, and are nota- 

 ble chiefly as presenting in a very striking manner the evidence of two 

 periods of growth. Wherever broken and whether large or small, the 

 crystals show a core of glassy, light to dark smoky quartz ; surrounding 

 this is a surface layer of white opaque quartz from 1 to 3 mm. in 

 thickness, crystallographically continuous with the smoky quartz, but on 

 many of the face*, especially those of the rhombohedrons, composed of 



