Eee SUS are Re TE ee aye yh ee EE 
ee? oh CA ete a ie cinch 
1 CRG TSM See Meese ee eg eee ce es te LS sk 
Ft iain tk ee re clean gine stckaae Bain ipa ety) Winey cE Neto atthe eae es. hn arate tan toel eT) WORE cate ae Se nn Cee Lee ne eae a a eR ip have ee ye ESTEE OR 
J. P. Cooke on Danalite from Rockport, Mass. 77 
very large amount of iron and zine entering into its composition, 
its color, luster, hardness, and other physical as well as chemical 
properties, all distinguish it from Helvin and prove the mineral 
to be a new species. As such I take great oe gta in so tnd 
it the name of Danalite, after Prof. James D. Dana, of New 
oe & name so honorably associated with American miner- 
way nal fragments of Danalite are not ee met ppc - 
the quarries at Rockport, and*small grains of it, as I 
already said, are quite generally disseminated pier’ the 
granite ledges which form the —— of Cape Ann. But 
arge masses of the mineral have not been obtained for some 
_ time, the portion of the rock in sete they were found having 
been long since quarried. The mineral was first supposed by 
the local collectors to be Rhodonite, and under this name good 
n 
near Glou , Mass. The mineral at this locality is more 
garnet- nike is in aps meade and contains a considerable silieemt of 
alumina associated with the glucina. An analysis of a specimen 
from this locality om) the ets a results : 
Silica, - - 29°88 
Protoxyd of i — . - - - - 28°13 
Oxyd of z - , - 8 - 1815 
Oxyd of ‘sauniinied: - : : - mae tf 
Glucina and alumina, : - - - 14-72 
Lime, - - - - - - ~ 688 
Magnesia, - s , : . traces 
Sulphur, - - - - = - - 4°32 
102°24 
Oxygen equiv. to ae . 2 ‘ 241 
99°83 
At Gloucester the Danalite i is associated with fluor pet which I 
have never recognized on the specimens from Rockport, although 
the granite, in which the mineral is imbedded, has at both local- 
ities a similar character. Danalite is also associated at both 
localities with two very remarkable varieties of lepidolite mica. 
These have also been analyzed and an account of the investiga- 
tion will be given in a future paper, 
