BAITS OF STRONTIA. 11] 



Dif. The long slender crystals are distinguished at once 

 from heavy spar, as the latter does not occur in such elon- 

 gated forms. From all the varieties of heavy spar, it differs 

 in a lower specific gravity and blowpipe characters ; from 

 the carbonates it is distinguished by not effervescing with 

 the acids. 



Obs. A bluish celestine, in long slender crystals, occurs 

 at Strontian island, Lake Erie ; Scoharie, Lockport and 

 Rossie, N. Y., are other localities. A handsome fibrous 

 variety occurs at Franktown, Huntington county, Pennsyl- 

 vania. Sicily affords very splendid crystallizations associ- 

 ated with sulphur : the preceding figure represents one of the 

 crystals. . The prisms are attached by one end, and being 

 crowded over the surface, they are in beautiful contrast with 

 the yellow sulphur beneath. 



The pale sky-blue tint so common with the mineral, gave 

 origin to the name celestine. 



Uses. Celestine is used in the arts for making the nitrate 

 of strontia, which is employed for producing a red color in 

 fire-works. Celestine is changed to sulphuret of strontium 

 by heating with charcoal, and then by means of nitric acid 

 the nitrate is obtained. 



strontianite. — Carbonate of Strontia. 



Trimetric. In modified rhombic prisms. M : M = 117° 

 19'. Cleavage parallel to M, nearly perfect. Occurs also 

 fibrous and granular, and sometimes in globular shapes with 

 a radiated structure within. 



Color usually a light tinge of green ; also white, gray and 

 yellowish-brown. Luster vitreous, or somewhat resinous. 

 Transparent to translucent. H =3*5—4. Gr =3*6— 3*72. 

 Brittle. 



Composition : strontia 70*2 carbonic acid 29*8. Fuses 

 before the blowpipe on thin edges, tinging the flame red ; 

 becomes alkaline in a strong heat ; effervesces with the 

 acids. 



Dif. Its effervescence with acids distinguishes it from 

 minerals that are not carbonates ; the color of the flame before 

 the blowpipe, from witherite ; and this character and the 



For what is celestine used 1 How do strontianite and celestine dif- 

 fer in composition 1 What are distinguishing characters of Btraotianite 1 



