142 LIME. 



datholite — Borosilicate of Lime. 



Trimetric. In hemihedral rhombic prisms. M : M=115* 

 26'. Crystals without distinct cleavage ; small and glassy. 

 Also botryoidal, with a columnar structure, and then called 

 botryolite. Color white, occasionally grayish, greenish, yel- 

 lowish or reddish. Translucent. H=5 — 5*5. Gr=2'9 

 —3. 



Composition: silica 37*4, lime 35*7, boracic acid 21*3 

 water 5*7. Botryolite contains twice the proportion of water 

 Rendered friable in the flame of a candle. Before the blow 

 pipe becomes opaque, intumesces and melts to a glassy 

 globule coloring the flame green. Forms a jelly easily with 

 nitric acid. I 



Dif. Its small glassy complex crystallizations without 

 cleavage are unlike any other mineral that gelatinizes with 

 acid, except some chabazites, from which it is distinguished 

 by tinging the blowpipe flame green, and having greater 

 hardness. 



Obs. Occurs in amygdaloid and gneiss. In Connecticut, 

 the finest come from Roaring brook, 14 miles from New 

 Haven. The Rocky Hill quarry near Hartford, Berlin, Mid- 

 dlefield Falls, Conn., and Bergen Hill and Patterson in New 

 Jersey, are other localities ; also in great abundance at 

 Eagle Harbor in the copper region, Lake Superior. 



Uses. Where abundant, as near Lake Superior, it raa) 

 be profitably employed in the manufacture of boracic acid. 

 It is suggested by Dr. C. T. Jackson as a good flux for the 

 copper ores. 



Okenite. In white fibrous seams or masses, consisting of delicate 

 fibers, and singularly tough under the hammer ; color whitish, yellowish 

 or bluish. H=45. Gr=2-28— 236. Composition, silica 57*0, lime 

 26'4, water 16-6. Fuses on the edges. Gelatinizes easily in muriatic 

 acid. From the Faroe Islands in trap ; also from Greenland. Dyscla 

 site is this species. 



Pectolite. Divergent, fibrous and resembling dysclasite. Luster weaft 

 pearly. H=4 — 5. Gr=269. Composition, silica 52'5, alumina, 36-1, 

 Sofia 3.0, water 3'4. Fuses to a white transparent glass. From the 

 Tyrol' and Fassa-thal. Also from Bergen Hill and Isle Royale, Lake 

 Superior. The Bergen Hill mineral has been called stellite. 



What is said of the crystals of datholite 1 How much boracic aci 

 oes datholite contain ] How is it distinguished ? 



