342 GEORGE F. KUNZ 



that thickness, has been set up as a monument in Franklin, 

 New Hampshire. 



By far the most extensive occurrence, however, is in the 

 Black Hills of South Dakota. Specimens were first brought 

 in by Prof. W. P. Jenney on his exploring expedition in 1876. 

 The exact locality is near French creek, 6 miles east of Custer, 

 in the county of that name. Here it exists in great quantity 

 and of fine quality, outcropping along a ledge for 500 feet in 

 a vein var3dng in thickness from a few feet up to 60. The 

 color, as usual, ranges through many shades, from faint pink 

 or even white, to the tint of a ripe watermelon, and in 

 places alters completely within a few inches. Contrary to 

 the general opinion, there is no evidence of its fading by ex- 

 posure to light, for outside portions, and even rolled bowlders, 

 show in some cases a fine deep coloring. 



Amethyst is a variety of quartz of a deep purple or bluish 

 violet color, shading almost to pink. Like ordinary quartz, 

 it is composed of silica, and the coloring is due to the presence 

 of oxides of managanse and iron. Its hardness is about 7, and 

 its specific gravity is slightly above 2.65. 



Fine gem material has been found in the United States, 

 though nowhere is it mined with any regularity. The localities 

 from which the finest specimens come are in Maine, Pennsyl- 

 vania, North Carolina, southern Virginia, and northeastern 

 Georgia, and several discoveries have been made recently in 

 the West. The main developments within the last few years 

 are the following: 



Deer Hill and Stow, in Maine, were noted localities some 

 time ago, but have not yielded much lately. At Denmark, 

 however, in the same state, Mr. G. R. Howe obtained many 

 fine crystals, and had a number of gems cut that were 

 very richly colored — equal to any from the Ural mountains. 



Another old locality was Upper Providence township, in 

 Delaware county, Pa. Here a large amount of amethyst 

 was obtained that yielded gems of the finest quality, one of 

 which was of 33 carats; and another, still larger, is in the 

 Lea collection in the National Museum at Washington. 



Virginia has only recently come into notice as a possible 

 source of amethyst production. Its occurrence, in beauti- 



