EMIGRANT DIAMONDS IN AMERICA. 



365 



ably unlike anything that they have ever seen. The first result of the 

 search has been the collection of large numbers of quartz pebbles, 

 which arc everywhere present, but which are entirely valueless. There 

 are, however, some simple ways of distinguishing diamonds from 

 quartz. 



Diamonds never appear in thoroughly rounded forms, like ordinary 

 pebbles, for they are too hard to be in the least degree worn by con- 

 tact with their neighbors in the gravel bed. Diamonds always show, 

 moreover, distinct forms of crystals, and these generally bear some 

 resemblance to one of the forms figured. They are never in the least 

 degree like crystals of quartz, which are, however, the ones most fre- 

 quently confounded with them. Most of the Wisconsin diamonds 

 have either 12 or 48 faces. Crystals of most minerals are bounded 

 by plane surfaces — that is to say, their faces are flat; the diamond, 

 however, is inclosed by distinctly curving 

 surfaces. 



The one property of the diamond, however, 

 which makes it easy of determination is its 

 extraordinary hardness — greater than that of 

 any other mineral. Put in simple language, 

 the hardness of a substance may be described 

 as its power to scratch other substances when 

 drawn across them under pressure. To com- 

 pare the hardness of two substances wu 

 should draw a sharp point of one across a sur- 

 face of the other under a pressure of the 

 fingers, and note whether a permanent scratch 

 is left. The harder substances will always 

 scratch the softer, and if both have the same 



hardness they may be made to mutually scratch each other. Since 

 diamond, sapphire, and ruby are the only minerals which are harder 

 than emery, the}' are the only ones which, when drawn across a rough 

 emeiy surface, will not receive a scratch. Any stone which will not 

 take a scratch from emery is a gem stone and of sufficient interest to 

 be referred to a competent mineralogist. 



The dissemination of information regarding the lake diamonds 

 through the region of the moraine shoidd serve the twofold purpose 

 of encouraging search for the buried stones and of discovering dia- 

 monds in the little collections of "lucky stones' 1 and local curios 

 which accumulate on the clock shelves of country farmhouses. When 

 it is considered that three of the largest diamonds thus far found in 

 the region remained for periods of seven, eight, and sixteen years, 

 respectively, in the hands of the farming population, it can hardly be 

 doubted that many other diamonds have been found and preserved as 

 local curiosities without their real nature being- discovered. 



Common forms of Diamonds. 

 The African stones most resem- 

 ble the figure above at the left 

 (octahedron). The Wisconsin 

 stones most resemble the figure 

 above at the right (dodecahe- 

 dron). 



