698 



INDEX 



Tetragonal system, 16, 65. 



trapezohedron, 75. 



trisoctahedron, 50. 



tristetrahedron, 57. 

 Tetrahedrite, 324, 596, 597. 

 Tetrahedron, 57. 



tetragonal tris-, 57. 



trigonal tris-, 56. 



hex-, 55. 



Tetrahexahedron, 49. 

 Thallium, tests, 577. 

 Thaumasite, 661. 

 Thenardite, 527, 638. 

 Thermonatrite, 639. 

 Thin sections colors, 216. 

 Third order of colors, 184- 

 Thirty-two types of crystals, 6, 47. 

 Thomsenolite, 663. 

 Thomsonite, 487, 673. 

 Thorite, 457, 679, 681. 

 Thorium, tests, 572. 

 Thoulet's solution, 263. 

 Thulite, 465. 

 Thuringite, 658. 

 Tiemannite, 627. 

 Tiger-eye, 435. 

 Tilasite, 653. 

 Tile ore, 338. 

 Tin, 584, 632. 

 Tincal, 523. 

 Tinstone, 348. 

 Titanates, 233. 

 Titanic iron ore, 346. 

 Titanite, 503, 603, 616, 667. 

 Titanium, tests, 569. 



oxides, 351. 

 Topaz, 458, 605, 681. 



false, 359. 



oriental, 342. 

 Topazolite, 444. 

 Topic parameters, 228. 

 Torbernite, 519, 644. 

 Torrensite, 667. 

 Total reflection, 167. 



reflectometer, 211. 

 Touchstone, 361. 

 Tough, 257, 258. 

 Tourmaline, 105, 473, 605, 612, 064. 



sections of, 177. 



tongs, 178. 

 Translucency, 275. 

 Transparent, 275. 

 Trapezohedron, hexagonal, 96. 



tetragonal, 75. 



trigonal, 109. 

 Tremolite, 431, 677. 

 Trichalcite, 643. 

 Triclinic system, 17, 129. 

 Tridymite, 361, 611, 681. 

 Trigonal axis, 14, 



equatorial, 105. 



Trigonal holoaxial, 108. 



polar, 110. 



prisms, 103, 106. 



pyramids, 102, 106. 



trapezohedron, 109. 



trisoctahedron, 50. 



tristetrahedron, 56. 

 Trimerite, 666. 

 Trimorphism, 220. 

 Triphylite, 653. 

 Triplite, 654. 

 Triploidite, 654. 

 Tripolite, 371. 

 Tripuhyite, 651. 

 Trisilicates, 234. 

 Trisilicic acid, 234. 

 Tritomite, 

 Trogerite, 652. 

 Troilite, 308, 630. 

 Trona, 401, 600, 639. 

 Troostite, 452. 

 Truncation, 22. 

 Tscheffkinite, 667. 

 Tschermigite, 638. 

 Tungstates, 236. 

 Tungsten, 587. 

 Tungstite, 668. 

 Turgite, 363, 633, 658. 

 Turingite, 498. 

 Turkey fat, 307, 392. 

 Turner's flux, 559. 

 Turquoise, 3, 510, 518, 604. 

 Twin axis, 138. 



Brazilian, 146. 



crystals, 138. 



interpenetrating, 141. 



lamellae, 142. 



plane, 138. 



reflection, 140. 



rotation, 138. 



spinel, 143. 



striae, 142. 



supplementary, 140. 

 Twinning, 138. 



lamellae, 142, 



polysynthetic, 142. 

 Twins, 137. 

 Tychite, 661. 

 Tyrolite, 643. 

 Tysonite, 679. 



U 



Ulexite, 524, 601, 663. 

 Ullmannite, 316, 625. 

 Umangite, 627. 

 Uniaxial crystals, 170, 184- 

 interference figure, 191. 

 Unit form, 23. 

 Uralite, 435. 

 Uralitization, 426. 



