Genth and Penfield — Contributions to Mineralogy. 387 



Calculated as 



fluorides. Molecular ratio. 



Ignition l - 57 



(Yt,Er)„0 3 * 47-58 58-05 -317) 



CeO,...". 0-83 0-96 -005 1-331 1 



(La,Di) 2 3 1-55 1-86 -009) 



CaO 19-41 27-03 -347 1 



Fe 2 3 and other admixtures 



not det. 8947 



This gives the formula CaFl 2 . (Yt,Er,Ce,La,Di)FJ 3 . 



8. Altered Zircon or Cyrtolite. 



Messrs. Geo. L. English. & Go. sent me for identification 

 crystalline groups of about 10 to 15 mm in size. They consisted 

 of bundles of crystals of columnar structure, radiating from 

 a center with their prismatic planes mostly obliterated and 

 terminated by rounded planes of the common pyramid of 

 zircon. 



They were stained with a greenish brown coating of the 

 oxides of iron and uranium, and, for purification, had to be 

 treated with dilute hydrochloric acid after which the color is a 

 very light greenish gray. Sp. gr. = 4-258. 



Associated with muscovite, flesh-colored orthoclase and 

 quartz, at Mt. Antero, Chaffee Co., Colorado. 

 The analyses gave : 



a. b. 



Ignition 2*42 2-47 



SiO a 30-38 30-66 



Zr0 9 61-38 60-89 (by diff.) 



Yt 2 3 . 0-60 0-65 



Fe 2 3 0-70 0-63 



U0 2 4-82 4-70 



MnO, MgO, CaO 1 traces traces 



100-30 100-00 



9. Lepidolite. 



A very beautiful variety of < lepidolite, associated with albite 

 and quartz, from Tanagama Yama, Japan, has been received 

 from Messrs. Geo. L. English & Co. It occurs in crystal- 



* The molecular weight of Tt and Er was found to be 126. The oxides were 

 yellow and the sulphates and oxalates slightly rose-colored. Although these 

 results are somewhat unsatisfactory, on account of the contaminated condition 

 and small amount of the material at my command, I thought them of sufficient 

 interest, to place them on record, as great pains were taken to arrive at the most 

 perfect separation of the constituents. Should it be my good fortune to get 

 larger quantities of this mineral, I intend to repeat this investigation. 



