ALUMINA. 



353 



CHABAZITE. 



[From tlic Greek -^u,a(ioc, tbougli ilie application is not known.*] 



Cliabazio. Haay, Ckavcland, Bcnilant anO Phillips. — Cliabazite. Thomson. — Rhombolicdral ZooUto, or 

 Chabazitc. Jameson. — Rbombocdrischcr Kuplion-Spath. Mohs. 



Description. Colour while or greyish. It occurs regularly crys- 

 tallized ; seldom massive. Primary form an obtuse rhombohedron. 

 Fig. 349. P' on P" 94-^ 46'. Cleavage parallel to the primary, but 

 seldom distinct. Fracture conchoidal and uneven. Lustre externally 

 splendent, internally glistening and vitreous. Hardness from 4.0 to 

 4.5. Specific gravity from 2.08 to 2. 10. Before the blowpipe, it 

 melts into a white frothy mass. Soluble by digestion in muriatic acid ; 

 solution precipitated by oxalate of ammonia. Gives out water by cal- 

 cination. 



This mineral sometimes resembles the obtuse rhombohcdrons of calcareous spar, but the 

 want of effervescence in acids will distinguish it. From several other of the trappcan mine- 

 rals, it differs in the action of acids, and of course in its crystalline form. 



Composition. Silica 50.14, alumina 17. 4S, lime 8.47, potash with soda 2.58, water 

 20.83 {Co7incl). 



Geological Situation. Like mesotype, stilbite, etc., this mineral is found in veins and 

 cavities in trap, greenstone and gneiss. 



LOCALITIES. 



Putnam County. Chabazite, in the primary form, has been found at Coldspring, asso- 

 ciated with stilbite. It is, however, of rare occurrence. 



Rockland County. It occurs in the primary form, associated with other trappean mine- 

 rals, in thin veins in the greenstone at Picrmont. It has not yet, however, been found near- 

 ly so common as in ilie similar formation at Bergen hill in A^ew-Jcrsey. The rhombohc- 

 drons are here usually luinute, and may easily be mistaken for calcareous spar, which occurs 

 in the greenstone in nearly the same form. The latter, however, wants the peculiar lustre 

 of the chabazite, and effervesces freely with acids. The crystals of chabazite, at this locality, 

 often have the edges and angles rounded as if by fusion. 



Westchester County. Chabazitc has been noticed near \Vcst-F''arnis, associated with 

 stilbite, heulandite and epidotc. 



Chabazite is often met with in the trap region of the Connecticut river. It occurs also on 

 mica slate at Chester, Mass., and at Hadlyme, Conn. 



MiN. — Part II. 



Thomson. Outlines of Minerahgi/, iSiC. I. 333. 



45 



