G. F. KUNZ — DIAMONDS FROM WISCONSIN. 639 



which the diamonds sent me for examination are said to have been found and three 

 of the diamonds, weighing, respectively, || of a carat (160,5 milligrammes), j^^ of a 

 carat (46 milligrammes) and ^2 of a carat (19.25 milligrammes). The largest of these 

 only would cut into a stone of any value. It is a hexoctahedral crystal, with rounded 

 faces, white, with a slight grayish-green tinge. It could be cut into a perfect bril- 

 liant of about j^g of a carat. On one side there is an L-shaped depression, with rounded 

 faces, in which there are minute grains of sand. The second in size is a slightly yel- 

 lowish elongated hexoctahedron. The surface of the crystal is not so smooth as that 

 of the larger crystal, and the entire surface is covered with small crystalline mark- 

 ings. The third in size is an elliptical hexoctahedral twin. The surface is dull and 

 the color white with a tinge of yellow. 



The sand which Mr. Nichols sent me I submitted to a microscopical examination, 

 and found that it contained, in addition to the quartz grains, magnetic iron; titanic 

 iron ; almandite garnet, in grains and in minute perfect dodecahedrons ; small, trans- 

 parent, brilliant crystals, none more than one-third the size of a pin's head, of what 

 appeared to be spessai-ite or essonite garnet ; a number of grains and rolled crystals of 

 monazite, and one small grain, said to be of platinum, which was lost before I could 

 examine it; thus resembling in many particulars the gold-bearing sands of Burke 

 county, North Carolina, and Hall county, Georgia. 



Interesting as this is, since it is a new locality for diamonds, it is very doubtful if 

 these sands will be more prolific or whether the discovery will have any more com- 

 mercial value than the gold sands of North Carolina and Georgia have proved to pos- 

 sess up to the present time. 



ON THE OCCURRENCE OF FIRE OPAL IN A BASALT IN WASHINGTON STATE. 

 33Y GEORGE FREDERICK KUNZ. 



During the month of August, 1890, James Allen, a jeweler of Yonkers, New Yoi-k, 

 detected fire opal among a pile of rocks that had been taken out of a well at a depth 

 of twenty-two feet on the farm of William Leosure, near Whelan, near the state line 

 of Washington, twenty miles southwest of Colfax, Washington state, and adjoining 

 Moscow, Idaho, in latitude 47°, longitude 117°, midway between the Coeur d'Alene 

 and the Nez Perces Indian reservation. It was found more or less plentifully, as the 

 last four feet of the rock contained cavities filled with fire opal. 



The opal occurs in altered and also in unaltered basalt. In the former most, if 

 not all, of the feldspar and pyroxene, as well as the green mass, appears to be altered. 

 Some original constitutent may have changed, but whether or not it is olivine is 

 diflicult to determine because of the crystal aggregate character of the pseudomorph. 

 The pieces varied from the size of a half pea to that of a hen's egg. The material is 

 found in a vesicular lava. The smaller nodules are very rich in color, but the larger 

 ones often have little or no play of colors. 



The opal may have been formed simultaneously with the formation of the rock, or 

 rather at a time that would be favorable to the formation of zeolites. The quality of 

 some of th.e small specimens examined was very fine, and if the material is so exten- 

 sive as supposed and is properly worked it is likely to bo one of the most promising 

 of our precious stones, from a financial point of view. 



LX LI 1 1— Bull. Gf.ol. Soc. Am., Vol. 2, 1890. 



