210 



DESCRIPTIVE MINERALOGY. 



ORDER 11. STRONTIA. 



This order includes the following : 



1. Celestine. 2. Stronlianite. 3. Barystrontianite. 



CELESTINE. 



[In allusion to the sky-blue colour which it sometimes possesses.] 



Strontiane Sulfate. Hanij. — Sulphate of Strontian. Ckaveland, Phillips and Thomson. — Prismatoidal Baryte. 

 Jameson. — Prismatoidischer Hal-Baryte. MoU. — Celestine. Beudant, Shepard and Dam. 



Fig. 47. Description. Colour usually white, but sometimes blue, red or 



yellowish red. It occurs regularly crystallized; also massive, 

 fibrous, radiated, stalactitic, etc. The primary form is a right 

 rhombic prism. Fig. 47. M on M 104° {Phillips); 104° 48' 

 (Haiaj); 104° 30' {Beudant.) Cleavage perfect parallel with the 

 sides of the primary, less so parallel with the base. Fracture 

 uneven. Lustre vitreous, inclining to pearly. Varies from trans- 

 parent to opaque. Hardness from 3.0 to 3.5. Specific gravity 

 from 3.60 to 4.00. Before the blowpipe, it behaves very nearly 

 like heavy spar, except that it communicates a red tinge to the flame. 



Composition. Sulphuric acid 43.64, strontia 56.36 (^ewdaM^). Formula SrO.SOj. But 

 it usually contains various foreign substances in small proportions. 



Geological Situation. In this State, celestine is usually associated with limestone, but 

 it does not seem to be peculiar to any geological epoch. It also accompanies gypsum, but it 

 has not been found here in the red sandstone and trap, as it is in various parts of England. 



localities. 



Cayuga County. In the rounded masses of dark coloured limestone which are found in 

 the slate on the Owasco outlet near Auburn, thin blades of this mineral, in the form of radii, 

 are not uncommon. It is usually white, and is associated with crystallized calcareous spar. 



Herkimer County. Fibrous celestine, of a bluish grey or blue colour, and closely resem- 

 bling some foreign specimens, occurs on the farm of James Crill, in the western part of the 

 town of Stark, where it is associated with gypsum. Iiuperfect crystalhne terminations are 

 also found intermixed with these fibres, which have a high lustre, and are transparent. The 

 same variety has also been observed in thin scams in the slate in a small water course near 

 Stephen Hammond's, and not far from the old road to Fairfield. It is often mixed in various 

 proportions with carbonate of lime.* 



* Vanusera. Nav-York Geological Reports, 1840. 



