128 RE-EXAMINATION OF AMERICAN MINERALS. 



23. OZARKITE, AN AMORPHOUS THOMSONITE. 



This mineral was described by Prof. Shepard as a new 

 species.* It occurs in irregular veins and masses in elseolite 

 at Magnet-cove, Arkansas. 



We are indebted to Mr. Markoe, of Washington, foi a large 

 quantity of the elseolite, from which we were able to obtain 

 the mineral in a pure state. Its color is white; structure gran- 

 ular to compact; hardness 5; specific gravity 2.24 (Shepard); 

 gelatinizes with hydrochloric acid. Two analyses gave 



1 2 



Silica 36.85 37.08 



Alumina 29.42") qi 13 



Peroxide of iron 1.55/ 



Lime 13.95 13.97 



Soda 3.91 3.72 



Water 13.80 13.80 



99.48 99.70 



This is the composition of thomsonite, and the mineral is a 

 massive variety of that species. 



The analyses give the formula fi Si+3^1 Si-f 7H=siliea 37.8, 

 alumina 31.5, lime 13.00, soda 4.80, water 12.90. 



Special examination was made for phosphoric acid, but in 

 the pure mineral none could be found, although in some im- 

 pure specimens that one of us had previously examined f it 

 existed in the form of apatite in considerable abundance, and 

 the specimens examined were pronounced a mixture of apatite 

 and a zeolite. 



This mineral was first referred to the zeolites by Mr. J. D. 

 Whitney, J who on a qualitative analysis found it to be a 

 hydrous silicate of alumina and lime, with a little soda. 



24. Dysyntribite, a Eock of indefinite Composition. 



The substance to which the above name was given by Prof. 

 Shepard § occurs in large masses in the northern part of the 

 state of New York. It is of a green color, sometimes mottled 

 with red. It resembles serpentine, but has a strongly argil- 

 laceous odor when moistened. 



* Amer. Jour. Science and Arts, 2d series, ii. 

 t Amer. Jour. Science and Arts, 2d series, ix, 430. 

 t Jour. Bost. Soc. Nat. Hist., 1849, p. 42. 

 #Kep. Amer. Assoc. Advan. Sci., vol. iv, 311. 



