INDEX TO MI.\EKAL<x;iC ( '( U.IJX'TIONS 



It:: 



< Irtborhombic crystals, 31. 

 Orthorhombic system, 31-34; normal 



group, 31-34; hemimorphic group, 



34. 

 Orthosllicates, '.i7-i<t."». 

 ox ids. 66-79. 



Pearly luster, 43. 



Phosphates, 117-22. 



Pinacoid, basal, 32, 35; brachy, 32; 

 clino, 35; macro, 32; ortho, 35. 



Plane, basal, 22, 26, 32, 35. 



Plane of symmetry, 8. 



Prism, brachy, 32; clino, 35; di- 

 hexagonal, 2»>; ditetragonal, 22; 

 hemi, 37; macro. 32; of the first 

 order, 21; of the second order, 

 22; of the third order. 23: ortho, 

 35; rhombic, 35; unit, 32. 



Pseudomorphs, 4t;. 



Pyramid, brachy, 33; clino. 36; 

 dihoxagonal, 26; ditetragonal, 21; 

 lit'ini. ::<;; hexagonal, 26; macro, 

 :::;: of the first order, 20; of the 

 second order, 21 : of the third 

 order, 23; ortho. 33; trigonal, 31; 

 unit. 20, 33. 



Pyritohedron, 17. 



Reniform, 40. 

 Resinous luster, 43. 

 Reticulated, 41. 

 Rhombic prism, 35. 

 unombohedral division. 27-29. 

 uoombohedron, 28. 

 Rock, definition of. 4. 



Scale of hardness, \± -»::. 

 Scalenohedron, hexagonal, 28; tet- 

 ragonal, 24. 

 Sectfle, 13. 

 Selenids, 51-61. 

 Silicates, s7-'.u. 

 Silky luster, hi. 

 simple mathematical ratio, law of. 



11-12. 



Sphenoid, tetragonal, 24. 

 Stalactitic, 41. 



Streak. 44. 

 St ii.it ions, 39. 



Subsllicates, 106 8. 



Sulfates, 124 -1~. 

 Mil lids. 51-61. 



Symmetry, axes of, 8; center of, 10; 

 definition, 7; law of. 7-10; planes 



of. S. 



Systems, crystallographic, 12. 



Tantalates, 1 1»;-17. 

 Tellurids, 51-61. 

 Tenacity, 43. 

 Tetragonal crystals, 20. 



prisms, 21. 



pyramids, 20. 



sphenoid. 24. 



scalenohedron, 24. 



trisoctahedron, see Trapezohe- 

 dron. 



tristetrahedron, 19. 

 Tetragonal symmetry. 10; axis of, 



10. 

 Tetragonal system. 20-24; normal 

 group. 20-22; pyramidal group, 

 23; sphenoidal group, 23-24. 

 Tetrahedron, IS. 

 Tetra hexahedron. 14. 

 Tita no-silicates. 115-16, 

 Trapezohedron, l.">; trigonal, 30. 

 Trichiiio crystals, 37-38. 

 Triclinic system. 36-38; symmetry 



of. :;7: normal group, 37-4<i. 

 Trigonal pyramid. 31. 



trapezohedron, 30. 



trisoctahedron, 15. 



tristetrahedron, 18. 

 Trigonal symmetry. '.»; axis of, 9. 

 Trisoctahedron. 15. 

 Tungstates, 128-29. 

 Twin crystals, 38-39. 



Uniaxial crystals, 25. 

 Unit plane, 31. 



prism. 32. 



pyramid, 20, •':•':. 

 Ira nates. 123-24. 



Vanadates, 1 1 7 11. 

 Vitreous luster, i".. 



Zeolites, 108. 



