SUPPLEMENT TO MINERAL LEXICON. 759 



1896. Prochlorite. Chester. 



On albite in druses at adit north of road at old mine, in fine, large masses. 

 (See p. 143.) 



1734. Pyrite. Northampton? "Marcasites," Pyrites. 



"Fragments of greenish sulphurous marcasite from Mount Tom and Holyoke, 

 each side Connecticut River." — John Winthrop, F. E. S., Ex. Vol. XV, Journal 

 Book of Royal Soc. Am. Jour. Sci., 1st series, Vol. XLVII, 1841, p. 289. 



1892. Pyrolusite. Wilhamsburg. 



E. S. Dana. Sys. Min. Localities, p. 1060. 



1897. Pyroxene. Diopside. Bald Mountam, Shelburne Falls, Massachu- 

 setts. 



In a dark, impure limestone. The crystals are themselves full of inclosed 

 limestone and effervesce strongly. They are in stout prisms up to an inch and a 

 half in length and a half inch across, greenish-white in color, strongly lustrous 

 on the prism faces and glossy; color, pale green. They are nearly square 

 prisms and recall the Canaan white pyroxenes. This mineral shows under the 

 microscope the brilliant colors and the strong prismatic cleavage of i)yroxene, 

 and a basal parting with many interposed twin laminne. The extinction reaches 

 33°. The specimen probably comes from a limestone bed of the Conwaj' schist, 

 which has been strongly and peculiarly metamorphosed by contact Avith granite. 



1888. Quartz. Rose quartz. Blandtbrd. 



Abundant by roadside near E. H. Osburii's. 



1892. Quartz. Amethyst. Grreenfield. 



The cavities in the red diopside-diabase, described on page 443, from the cut 

 through the trap ridge made for the electric railroad, contain small amethysts of 

 great beauty, which are interi^enetration twins of model-like perfection. The 

 twinning plane is O (0001). 



1897. Rhodonite. "Cumaing-ham" (for Cummino;-toiT.) 



G. P. Merrill. Stones for building and decoration, p. 174. Cites Kuuz, 

 Min. Eec, 1887. 



