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DESCRIPTIONS OP MINERALS. 



Aragonite. 



Trimetric. In rhombic prisms; I A 7=116° 10'. Cleavage 

 parallel with I. Usually in compound crystals having the 

 form of a hexagonal prism, with uneven or striated sides ; 

 or in stellated forms consisting of two or three flat crystals 

 crossing one another. Transverse sections of some of the 

 compound crystals are shown in figs. 1 to 4. 



in I I m 



Occurs also in globular and coralloidal shapes ; also in 

 fibrous seams in different rocks. 



Color white or with light tinges of gray, yellow, green and 

 violet. Lustre vitreous. Transparent to translucent. H.= 

 3-5-4. G. = 2-931. 



Composition. Same as for calcite, and its action before 

 the blowpipe and with acids is the same, except that it falls 

 to powder readily when heated. Some varieties contain a 

 few per cent, of strontium carbonate, bnt this is not an 

 essential ingredient. Distinguished from calcite by the 

 absence of the cleavage of the latter, as well as the crystal- 

 line form ; also by its higher specific gravity. 



Obs. Aragonite occurs mostly in gypsum beds and in 

 connection with iron ores ; also in basalt and other rocks. 

 The coralloidal forms are found in iron ore beds, and are 

 called Flos ferri, flowers of iron. They look like a loosely 

 intertwined or tangled white cord. 



The flos-ferri variety occurs at Lockport with gypsum ; 

 also at Edenville, at the Parish iron ore bed in Kossie, and 

 in Chester County, Pennsylvania. Aragon in Spain affords 

 six-sided prisms of aragonite, associated with gypsum. This 

 locality gave the nameto the species. Also found at Bilin, 

 in Bohemia, Tarnowitz in Silesia, and other places. 



