1 917 ] Eakle: Minerals Associated ivith Crystalline Limestone 343 



Gordon Surr, 

 analyst 



SiO, 

 FeO 

 CaO 

 MgO 

 Igu. 



36.02% 



2.82 

 34.36 

 24.74 



1.25 



37.46% 



2.94 

 35.14 

 25.32 



99.19 



100.86 



G = 3.078 



The occurrence of the monticellite and waluewite in close associa- 

 tion is interesting because both have crystallized from the same silicate 

 mixture and the waluewite may be viewed as having the composition of 

 monticellite plus the spinel and alumina hydrate molecules. In the dis- 

 cussion of the members of the clintonite group of silicates, Clarke and 

 Schneider make the suggestion that waluewite may have the monti- 

 cellite molecule in addition to its spinel and olivine molecules although 

 no direct association of the two minerals was then known. Here we 

 have the two crystallized together from a silicate mixture in which the 

 monticellite molecule largely predominated and their crystallizations 

 were practically simultaneous. The composition of the waluewite 

 suggests a mineral mixture of monticellite -4- olivine -4- spinel -j- 

 diaspore in an approximate ratio of 6:1:5:6. 



These monticellite and waluewite masses have in all probability 

 been formed by the metamorphism of the brucite-limestone, while the 

 common vesuvianite and diopside, which also occur in the blue calcite, 

 but not associated with the monticellite and waluewite, are evidently 

 products of metamorphism of the ordinary limestone, which has little 

 magnesia. The former two were quite local in their development and 

 were soon exhausted, while the latter are the abundant minerals of 

 the quarry. 



Wilkeite. — This interesting lime mineral with the four acid radicals 

 has already been described, 7 so only the essential parts of that descrip- 

 tion will be given here. Boulders of blue calcite containing the 

 granular pink wilkeite had just been blasted from the face of the 

 quarry on the day the writer visited it, and fortunately specimens were 

 collected of a mineral which would otherwise have gone unnoticed to 

 the crusher. 



The wilkeite occurs as small grains and minute hexagonal prisms 

 disseminated through the masses of blue calcite. The mineral is clear 



i Amer. Jour. Sci., vol. 37, p. 262, 1914. 



