324 Knopf and Schaller — Two New Boron Mineral*. 



the variety wiluite. The magnetite shows o \ 111 \ , m\ 311 • large 

 with a {100}, d\110\ small. The hulsite is quite abundant 

 and is sometimes intergrown with magnetite and vesuvianite. 

 Its characteristic features are its strong submetallic luster, 

 black color, good prismatic cleavage, and tendency toward a 

 tabular development. Its surface weathering is entirely 

 similar to that of magnetite, and on casual inspection the hul- 

 site may easily, be confounded with that mineral. The tabu- 

 lar individuals of hulsite vary in thickness from a fraction of 

 a millimeter to over a centimeter in the maximum noted. 

 Under the microscope few additional features appear. A 

 small amount of diopside is found to be associated with the 

 other minerals already enumerated. The hulsite is completely 

 opaque and appears black in reflected light. The thin sections 

 show that magnetite is often intimately intergrown with the 

 hulsite, from which it is distinguished by its bright metallic 

 reflection. 



The other mineral, for which we propose the name paigeite. 

 in honor of Mr. Sidney Paige of the Geological Survey, 

 was found at two localities, at Brooks Mountain in loose 

 blocks, and at Ear Mountain, 40 miles to the northeast, in situ. 

 It is a lustrous coal-black mineral of foliated appearance. The 

 material from Brooks Mountain was subjected to chemical 

 analysis. A thin section of the matrix shows vesuvianite, cal- 

 cite, hedenbergite, a small amount of biotite, and arsenopyrite 

 in sporadic grains. Paigeite is abundant, and is often in capil- 

 laiy or trichite-like forms transfixing the various other associ- 

 ated minerals. It is opaque, and appears black in reflected 

 light. Other contact-metamorphosed limestones, from the 

 near vicinity from which the paigeite rock was collected, show 

 the following combination of minerals : chondrodite, spinel, 

 magnetite, and calcite ; a fibrous green boron mineral resem- 

 bling ludwigite, and galena ; highly ferriferous sphalerite, 

 galena, pyrrhotite, diopside, calcic plagioclase, fluorite and cal- 

 cite. 



At Ear Mountain a granite intrusion has produced an 

 extensive development of contact-metamorphosed limestones, 

 largely consisting of lime-silicate hornfels. Some of these are 

 flecked with paigeite and chalcopyrite. Under the microscope 

 this variety of hornfels is seen to consist of a confused inter- 

 growth of calcite, zonally banded tourmaline, pleochroic in 

 tones of blue and brown, vesuvianite, fluorite and zoisite, with 

 accessory phlogopite, chalcopyrite, and magnetite. Paigeite 

 fibers and matted aggregates are embedded in the various con- 

 stituent minerals, especially in the tourmaline and calcite. With 

 the paigeite-bearing hornfels is associated a tourmaline-scapo- 



