344 University of California Publications in Geology [Vol. 10 



and glassy and usually pink but some grains are yellow. The mineral 

 is essentially a calcium phosphate of the apatite group, with much of 

 the phosphate replaced by the silicate, sulphate and carbonate mole- 

 cules. A summary of the properties of the mineral are : Hexagonal 

 system ; c = 0.730 approx. Prominent forms ( 10T0 ) (1120) ( 10T1 ) and 

 (0001). Imperfect basal cleavage. H = 5. G = 5.234. Color pale 

 pink or yellow. Luster vitreous or greasy. Optically uniaxial, negative. 

 n = 1.640 ± .005 ; n — n = .0004. 

 Chemical composition is : 



Si0 2 



9.62% 



CaO 



54.44 



MnO 



0.77 





20.85 



so 3 



12.28 



CO, 



2.10 



ELO 



tr. 





100.06 



The formula derived from this analysis is : 



3Ca 3 (P0 4 ) 2 • 3Ca,Si0 4 . 3CaS0 4 . CaC0 3 . CaO. 

 In order to better show its relation to apatite this may be written : 



3Ca 3 (P0 4 ) 2 . CaC0 3 + 3Ca 3 [(Si0 4 ) (S0 4 )] • CaO. 

 During the past summer more of the wilkeite was observed in the 

 quarry quite near the contact with the monzonite, in crystals several 

 centimeters long, coated with its alteration product. This alteration 

 substance coats the original grains and, in the absence of analyses, 

 was thought to be okenite from its optical characters. There is a 

 possibility that the delicate fibers optically tested are okenite ; they 

 cannot be separated from the intermixed wilkeite and their exact 

 composition cannot therefore be determined. Much white secondary 

 material has more recently been found which, as analyses show, does 

 not have the ratio of lime to silica in the proper proportions for okenite. 

 Since it is different from any known silicate, it is described below as a 

 new mineral. 



Crestmoreite, a New Mineral. — Since the appearance of the paper 

 on wilkeite. blue calcite has been found in the Commercial Rock 

 quarry containing much soft white material disseminated through it 

 in small bunches, as if it were an alteration, in place, of former 

 crystals and grains included in the carbonate. Some of the blue calcite 

 also contains large individuals of this white material having sharply 



