330 A TREATISE ON METAMORPHISM. 



Scolecite: 



H 2 CaAl 2 Si 3 O n .2H 2 0. (Dana agrees with Groth. ) 



Monoclinic. 



Sp. gr. 2.16-2.4. 



Analcite: 



Na 2 Al 2 Si 4 12 .2H 2 0. (Dana agrees with Groth. ) 



Isometric. 



Sp. gr. 2.22-2.29. 



Apophyllite: 



H,KCa 4 Si 8 24 .4*H 2 0. (Dana agrees with Groth. ) 



H u Ca 4 Si 6 23 . 



Tetragonal. 



Sp. gr. 2.3-2.4. 



H 6 Ca 2 Al 4 Si 11 33 .7H 2 0. (Dana varies from both, but is nearer Groth. His formula is 



H 4 CaAl 2 Si 6 18 .3H 2 0.) 

 CasAleSisOig.ieHjO. 

 Monoclinic. 

 Sp. gr. 2.25. 



Heulandite: 



H 4 CaAl 2 Si 6 ls . 3H 2 0. ( Dana agrees with Groth. ) 



Ca 3 Al 6 Si 18 48 .16H 2 0. 



Monoclinic. 



Sp. gr. 2.18-2.22. 



Stilbite (desmine): 



Ca 4 Al 8 Si 16 48 .18H 2 0. (Dana's formula is nearly the same as Clarke's: 



H 4 (Na 2 Ca)Al 2 Si 6 13 .4H 2 0.) 

 Ca^AleSijsO^.lSH.O. 

 Monoclinic. 

 Sp. gr. 2.094-2.205. 



Phillipsite: 



(K 2 Na 2 Ca) 3 Al 6 Si 10 O 32 .12H 2 O. (Dana's formula is nearly like Clarke's: 



(K 2 Ca)Al 2 Si 4 12 .4JH 2 0.) 

 K 2 Ca 2 Al 6 Si 12 86 .14H 2 0. 

 Monoclinic. 

 Sp. gr. 2.2. 



Harmotome: 



Ba 3 Al 6 Si 10 O 32 .12H 2 O. (Dana varies from each. His formula is (K,Ba)Al 2 Si 5 14 .5H 2 0.) 



Ba 3 Al 6 Si 14 O 40 .14H 2 O. 



Monoclinic. 



Sp. gr. 2.44-2.50. 



