862 



Mr. Levy on Two New Minerals. 



{Nov. 



matrix, in the cavities of which it is found, greatly resembles 

 lava, but upon a close examination, I found it entirely composed 

 of small grains and crystals of olivine, several of which I have 

 detached, and measured by means of the reflective goniometer. 

 Dr. WoUaston, with his usual kindness, has examined chemi- 

 cally a small quantity of Herschelite, and has found it contains 

 silex, alumina, and potash. These are also the constituent parts 

 of felspar and amphigene, but the new substance most certainly 

 differs from both by its crystallographical and other characters. 

 The form of the crystals indicates that they are derived either 

 from a rhomboid or a six-sided prism, but the exact dimensions 

 of the primitive form I cannot give, on account of the difficulty 

 of obtaining accurate measurements. The face p is always dull 

 and curved, the faces b^, though sometimes sufficiently brilliant 

 for measurement, are generally composed of a number of planes 

 slightly raised one above the other. The mean between several 

 measurements gives 



p, b' = 132° b% ¥ = 124' 45' 



If, therefore, we suppose the primitive form to be a six-sided 

 prism, and the faces h' to be the result of a decrement by one 

 row on the terminal edges, the ratio between one side of the base 

 and the height of the prism will be nearly that of equality. I 

 could obtain no cleavage either parallel to the base of the prism, 

 or in any other direction. The mean of two experiments to 

 determine the specific gravity gives 2* 11. The fracture is con- 

 choidal, and this substance is easily scratched by the knife. 



Phillipsife, 



Herschelite , is accompanied by another substance, which, I 



also believe, belongs to a distinct species, for which I propose 



the name of Phillipsite, in honour of Mr. W. 



Phillips, whose contributions to mineralogy Fig. 2. 



are so numerous and so valuable. 

 idi This substance occurs in minute white, 

 jtfdnslucent, and opaque crystals of the form 



leprdsented by fig. 2. In the specimens from 



'iA.ci Reale, these crystals are lengthened, i 



adhere closely together radiating from a^oJ ^> 



common centre, and forming globular concre«jjj84 sd 



tions. It is also found in separate crystals' 

 ) disseminated on the matrix with comptonLte 

 u,aind I other |substances, in specimens from 

 ' v]M'esuviusi 'The form of these crystals is the 



same as that of harmotorae, Haiiy has called 



dodeiuiedf^y dAid the iucidences ol* the faces are nearly the same. 

 . iiEi'caMMe^uence of these analogies, Ihis substance has been 

 ' 'oobftkleved by some mineralogisis as identical with haimotome. 



