INDEX TO MINERALOGIC COLLECTIONS 



143 



Orthorhombic crystals, 31. 

 orthorhombic system, 31-34; normal 



group, 31-34; hemimorphic group, 



34. 



Orthosilieates, 97-105. 

 Oxids, 06-79. 



Pearly luster, 43. 



Phosphates, 117-22. 



I'inacoid, 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, 26; 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, 46. 



Pyramid, brachy, 33; clino, 30; 

 dihexagonal, 26; ditetragonal, 21; 

 hemi, 30; hexagonal, 26; macro, 

 33; of the first order, 20; of the 

 second order, 21; of the third 

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

 unit. 20. 33. 



r.viitohedron, 17. 



Reniform, 40. 



Resinous luster, 43. 

 Etetieulated, 41. 

 Rhombic prism, 35. 

 Rhombohedral division. 27-29. 

 Rboinbohedron, 28. 

 Rock, definitiqn of, 4. 



Scale of hardness, 42-43. 

 S< alenohedron, hexagonal, 28; tet- 

 ragonal, 24. 

 Sectile, 43. 

 Selenids, 51-61. 

 Silicates. 87-91. 

 Silky luster, 43. 



simple mathematical ratio, law of, 

 11-12. 



Sphenoid, tetragonal, 24. 

 Stalaetitic, 41. 

 Streak. 44. 

 Striations, 39. 



Subsilicates, 100-8. 

 Sulfates, 124-27. 

 Miltids, 51-61. 



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

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

 of, 8. 



Systems, crystallographies 12. 



Tantalates, 110-17. 

 Tellurite, 51-01. 

 Tenacity, 43. 

 Tetragonal crystals, 20. 



prisms, 21. 



pyramids, 20. 



sphenoid, 24. 



scalenohedron, 24. 



trisoctahedron, sec 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, 18. 



Tetrahexahedron, 14. 



Titano-silicates, 115-10. 



Trapezohedron, 15; trigonal, 30. 



Triclinic crystals, 37-38. 



Triclinic system, 30-38; symmetry 

 of, 37; normal group, 37-40. 



Trigonal pyramid, 31. 

 trapezohedron, 30. 

 trisoctahedron, 15. 

 tristetrahedron, 18. 



Trigonal symmetry, 9; axis of, 9. 



Trisoctahedron, 15. 



Tungstates, 128-29. 



Twin crystals, 38-39. 



Uniaxial crystals, 25. 

 Unit plane, 31. 



prism, 32. 



pyramid, 20, 33. 

 Uranates, 123-24. 



Vanadates, 117-22. 

 Vitreous luster, 43. 



Zeolites, 108. 



