W. E. Ford— Mineral Notes. 503 



the usual broad signal showing the colors of the continuous 

 spectrum. The signals were faint but distinct and well sepa- 

 rated from each other. This peculiar phenomenon was more 

 clearly explained when a thin section of the mineral was placed 

 between a source of white light and the slit of a spectroscope. 

 The resulting spectrum seen through the instrument showed 

 strong absorption, there being two distinct bands of light, one 

 rather narrow in the red and the other somewhat broader in 

 the yellow-green with only faint light showing in the other 

 parts of the spectrum. The green band was found to occupy 

 approximately that portion of the spectrum between 520/x/x 

 and 575/Lt/A and the red band that portion between 650/zft and 

 700/-c/x. The indices of refraction of these two bands of light 

 as determined by means of the prism were for green, n — 2*19 

 and for red, n — 2*16. The results are given only to the 

 second place of decimals because of probable errors involved 

 in using such a small angle prism (15°) and the difficulty of 

 the measurements due to the faint signals obtained. The 

 index of refraction for sodium light, which could not be mea- 

 sured on account of the absorption of that light, was calculated 

 to be approximately 2 '18. 



III. New Occurrences of Spangolite. 



Spangolite, Cu 6 A1C1SO 10 .9H 2 O, was first described in 1890 

 by S. L. Penfield.* The original specimen, now preserved in 

 the Brush Mineral Collection, showed a group of line hex- 

 agonal crystals proved to be rhombohedral by etching figures, 

 associated with cuprite and azurite. The exact locality of the 

 occurrence of this specimen is not known, but is supposed to 

 be in the neighborhood of Tombstone, Arizona. Later, Miersf 

 discovered the same mineral on specimens from Cornwall, and 

 proved that it was hemimorphic in symmetry. More recently 

 Pellouxij; has described its occurrence from Arenas, Sardinia. 



Within the last year the Brush Collection has acquired 

 through Mr. Lazard Calm specimens of spangolite from two 

 American localities. The first specimen "came from the Cop- 

 per Queen Mine at Bisbee, Arizona. The specimen consists of 

 a granular mass of cuprite with small crystals of the mineral 

 upon one surface. "With these crystals is one small but well 

 defined crystal of spangolite. The crystal shows a tapering 

 hexagonal pyramid with prominent horizontal striations. It is 

 terminated on the free end by a prominent basal plane so that 

 the crystal presents a strikingly hemimorphic character. Of 



* This Journal, xxxix, 370, 1890. 

 f Nature, xlviii, 426, 1893 ; Min. Mag., x, 273, 1894. 



% Ann. Mus. Civico Storia Nat. Genova, iv, 194, 1909 ; Ref . Zs. Kr. 1, 493, 

 1912. 



