XXXII. TURQUOISE, ODONTOLITE, VARISCITE 257 XXXIII. JADE (NEPHRITE OR GREENSTONE, _Jadeite_) 260 XXXIV. SPODUMENE (_Kunzite_, _Hiddenite_), IOLITE, BENITOITE 265 XXXV. EUCLASE, PHENAKITE, BERYLLONITE 269 XXXVI. ENSTATITE (‘_Green Garnet_’), DIOPSIDE, KYANITE, ANDALUSITE, IDOCRASE, EPIDOTE, SPHENE, AXINITE, PREHNITE, APATITE, DIOPTASE 271 XXXVII. CASSITERITE, ANATASE, PYRITES, HEMATITE 281 XXXVIII. OBSIDIAN, MOLDAVITE 283 PART II—SECTION C ORNAMENTAL STONES XXXIX. FLUOR, LAPIS LAZULI, SODALITE, VIOLANE, RHODONITE, AZURITE, MALACHITE, THULITE, MARBLE, APOPHYLLITE, CHRYSOCOLLA, STEATITE OR SOAPSTONE, MEERSCHAUM, SERPENTINE 285 PART II—SECTION D ORGANIC PRODUCTS XL. PEARL, CORAL, AMBER 291 TABLES I. CHEMICAL COMPOSITION OF GEM-STONES 300 II. COLOUR OF GEM-STONES 301 III. REFRACTIVE INDICES OF GEM-STONES 302 IV. COLOUR-DISPERSION OF GEM-STONES 303 V. CHARACTER OF THE REFRACTION OF GEM-STONES 303 VI. DICHROISM OF GEM-STONES 304 VII. SPECIFIC GRAVITIES OF GEM-STONES 305 VIII. DEGREES OF HARDNESS OF GEM-STONES 305 IX. DATA 306 INDEX 307 LIST OF PLATES PAGE I. GEM-STONES (in colour) _Frontispiece_ II. REFRACTIVE INDEX DIAGRAM 36 III. INTERFERENCE FIGURES 48 IV. JEWELLERY DESIGNS 62 V. JEWELLERY DESIGNS 88 VI. APPLIANCES USED FOR POLISHING DIAMONDS 102 VII. POLISHING DIAMONDS 103 VIII. SLITTING AND POLISHING COLOURED STONES 104 IX. FACETING MACHINE 105 X. LAPIDARY’S WORKSHOP AND OFFICE IN ENGLAND 106 XI. LAPIDARY’S WORKSHOP IN RUSSIA 107 XII. FRENCH FAMILY CUTTING STONES 108