THE MINERALS OF IDAHO 



449 



of Col. W. A. Roebling. In commenting upon the latter specimen. 

 Colonel Roebling writes as follows: "Although I have at least 30 

 anglesites, the crystal you sent is the best of its class * * *. The 

 Broken Hill specimens are different in habit and more orange in 

 color * * *. Yours is like those from Monte Poni, Sardinia, 

 embedded in galena, frequently with a black heart of unchanged 

 galena. Occasionally there has been too much sulphur for the lead 

 to absorb, leaving a cavity with a perfect little crystal of sulphur 

 in it." 



153 154 



Figs. 153-154.— Anglesite. Hypotheek mine, Shoshone County 



The largest crystal observed at the mine was about 4 cm. in 

 diameter, but some as large as an egg are said to be frequently 

 obtained. Cavities lined with crystals up to 1 cm. in diameter 

 occur everywhere in the galena. Where a little work with a hack 

 saw and a light hammer would yield a beautiful specimen, the lumps 

 of galena are struck, by the miners, with a heavy hammer. If a 

 fairly symmetrical group of crystals breaks out it is preserved, but 

 when, as commonly happens, the anglesite flies to pieces or the 

 crystals break loose from the matrix, the whole is thrown away. 



These crystals from the Hypotheek mine are ideally suited for 



measurement on the reflecting goniometer. The accompanying 



Figures 148 to 156 show the predominant habits observed. The 



first 10 examined and described in the paper cited were measured 



54347— 26f 30 



