﻿W. E. Hidden — Contributions to Mineralogy. 205 



tion last summer, in the search for spodumene gems, on this 

 Morton tract, the quartz crystals above described frequently 

 occured in the top soil; the miners here call them " hiddenite- 

 quartz." 



In a period of three months' work, nine well defined pockets 

 of yellowish and emerald-green spodumene (hiddenite) were 

 discovered, but the aggregate yield was comparatively small. 

 Yery few perfect crystals were found suitable for gems, but 

 some were successfully cut. It is thought that the material 

 may improve when the hard rock is reached; at a depth of 20 

 feet the loose sandy disintegrated rock remains unchanged. 

 With the spodumene were found a few beryls of some merit as 

 to transparency and color ; great numbers of quartz crystals, 

 some of remarkable form ; a few brilliant and highly modified 

 crystals of black tourmaline (see below) ; some monazite and 

 many small crystals of ruby-red rutile mostly associated upon 

 or within quartz crystals. Among the spodumene crystals 

 were a few that were doubly-terminated and of a new type of 

 form for the region, the prismatic planes being only slightly 

 developed. These crystals were nearly colorless, quite large 

 and semi-opaque. 



The following communication from Professor Des Cloizeaux 

 (dated Paris, Feb. 4, 1886) gives the values of the* indices of 

 refraction of this species, and shows that its refractive power 

 is only slightly higher than that of tourmaline : 



"Physically the hiddenite is identical with the yellow triphane 

 (spodumene) of Brazil. Thanks to the new refractometer just 

 announced by Emile Bertrand, in the Bulletin de la Societe Min- 

 eralogique, it is now possible to obtain the three indices of refrac- 

 tion from uncut or cut sections. A first approximation gave 

 for hiddenite a=V§11 \ /5=1'669; ^=1*651 for yellow rays. 

 I afterwards found fjjj.== 1*669 for the triphane of Brazil, cut on 

 the prism." 



Black Tourmaline. — The tourmalines, incidentally alluded 

 to in the preceding note on spodumene, occur implanted in 

 cavities similar to the other crystals of this region. They 

 are noteworthy from the brilliancy and number of the planes 

 presented. With a hand goniometer I identified the following : 

 0, 7, 2-2, R, 1, J, -J, |, f, 2, 3 and -| 3 — twelve planes in all. 

 Several others were noticed but their angles could not be de- 

 termined with the means at hand. One crystal presented only 

 the planes f i?, \R and all equally developed, §i£ being new. 

 None of the crystals were over one inch in diameter and two 

 inches long. On many of them, minute ruby-red quadratic 

 crystals of rutile were implanted, having the basal plane. 

 Through thin edges these tourmalines had a deep brown color, 

 and the smaller crystals were translucent. %R measured on 



