:98-96 



Miner a logical Notices. 213 



be this mineral. H. about 6-5. G.=2'732-2-733. Massiire, 

 granularj strongly coherent ; grains with one perfect cleavage and 

 indications of another oblique to it. Lustre vitreous, approach- 

 ing to pearly upon the cleavage faces ;. translucent ; color green- 

 ish white. The smoky blue mineral from Perth generally circu- 

 lated among mineralogists as bytovvnite, is a mixture apparently 

 of the true bytownite with what appears to be a black horn- 

 * blende. Composition of the bytownite according to Mr. Hunt, 



§i ^l Ca 



47-40 30-45 14-24 



47*30 



Mr. Hunt deduces from these results and the characteristics of 

 the species, that it is anorthite. [The oxygen ratio for the pro- 

 toxyds, peroxyds and silica is 1 : 2-66 : 4*62, which is wide from 

 1:3:4, the ratio for anorthite ; and therefore, it must be, if this 

 species, an impure variety of it- The mineral thiorsauite of 

 Grenth, has nearly the same composition according to Genth's 

 analysis ; but this Iceland feldspar is considered impure anorthite 

 by Rammelsberg.] 

 ^ 4. Lahradorite. — Common in boulders from Labrador to Can- 



ada West, but has not been observed in place. A specimen from 

 Drummond, C. W., of a lavender blue color and pearl-gray opa- 



iig 



fe 



Na 



K 



TT 



0-87 



0-80 



2-82 



0-38 



200 

 1-80 



lescence, had the sp. gr. 2 697, and consisted as follows : 



Si 



51 



Ca 





Ag 



]?ra 



K 



fi 



54-70 



29-80 



11-42 



0-36 



trace 



2-44 



0-33 



0-40 



:99-35 



Mr. Hunt observes with regard to the water in this and other 

 feldspars, that he agrees with Delesseand Laurent, in considering 



It as belonging to the constitution of the mineral and not hygro- 

 scopic. 



5. Raphilite of Thomson. — This mineral from Lanarck, C. W., 

 is tremolite. H. = 5-5. G. (in powder) =2-845. Lustre vitreous 

 silky; color grayish or greenish-white, becoming reddish on 



< Weathered surfaces. Composition : 



Si Si Ca Mg tQ Sin ]?ra t. 

 55-30 0*40 13-36 22*50 6-30 traces O'SO 025 iga 0-30=:90-Sl 



Oxygen 28-'72 019 S'SO S'YS 1-40 0-21 0-04 



6. Retinalite and Serpentine. — The retinal ite of Thomson 

 "^as founded on a serpentine from near Grenville, sent him by 

 Dr. Holmes, and a portion of the same specimen he gave Mr. 

 Hunt for analysis; other specimens were procured at the locality. 

 ^ fills seams or penetrates granular limestone near a trap dyke. 

 H.^3-5. G.=2-494"2-525-2-476. Lustre resinous; streak white; 

 color honey yellow passing into oil green and olive green; trans- 

 lucent; fracture conchoidal. Composition : 



Si Pe Mg S-a fl 



I- 39-34 1-80 4302 trace 15-09 = 99-26 



IL 4010 1-90 41*65 0-90 15'00 = 99'65 



