Adamantine lustre,28glimmering,29glinting, or glistening,29lustreless,29shining,29splendent,29Agate,11Almandine,101Amethyst,11oriental,85sapphire,85Amorphous stones and their characteristics,23Analysis,5Aplome,101Asters, or asteriated stones,82,87-91Azure-stone,103Beryl,10,94colours of, in dichroscope,34Beryllium,10Bezils,66Black stones, list of,79Blue sapphire, composition of the,10stones, list of,77Bone-turquoise,106Break, as opposed to cleavage,19Brilliant-cut stones,66Brown stones, list of,76Building up of crystals,13Burnt, or pinked topaz,92Cabochon-cut stones,64(the double),65(the hollow),65Carbonate series,11Carbuncle,102,103Cat of Egypt,89Cat's eye stones,82,87-91list of (see "Chatoyant Stones"),78Ceylonese cat's eye (see "Cat's eye")Change of colour (not to be confused with "Play of colour" and "Opalescence," which see; see also "Fire"),36Characteristics of precious stones,1,3Chatoyant stones, list of,78Chemical illustration of formation of precious stones,8Chloride of palladium in dichroscope,34Chrysoberyl,88Chrysolite,11ordinary, or "noble",85oriental,85Cinnamon stone,102Claims of precious stones,4Cleavage affecting tests,43and "cleavage" as opposed to "break",19,22Colour,26,28,30,32Colourless stones, list of,75Colours and characteristics of the various opals,35,36of precious stones, list of,75-79Common garnet,101opal,35Composite crystals,13Composition of paste, or strass, for imitation stones,71Composition of precious stones,7Converted stones,72Corundum,82Crown portion of stones,65,66Crystalline structure, physical properties, of13Crystallography,14Crystals, axes of symmetry,15groups of,15,16planes of symmetry,15systems of,16(1) Cubic—isometric, monometric, regular,16(2) Hexagonal—rhombohedral,16(3) Tetragonal—quadratic, square prismatic, dimetric, pyramidal,16(4) Rhombic—orthorhombic, prismatic, trimetric,16(5) Monoclinic—clinorhombic, monosymmetric, oblique,16,17(6) Triclinic—anorthic, asymmetric,16,17treatment of,14Culasse portion of stones,66Cullinan diamond (see also "Stars of Africa"),22,64,68,80Cutting of precious stones,3,4,62Cymophane,90Definition of a precious stone,1Diamond, characteristics of the,80composition of the,10(sapphire),86unique,10(zircon),99Diaphaneity,26,28Diaphanous stones,28Dichroscope,33how to make a,33how to use a,34Dimorphism in precious stones,25Double cabochon-cut stones,65refraction (see "Refraction")Doublets,72Electric and magnetic influences,57experiments with precious stones and pithball and electroscope,57experiments with tourmaline,58,59Emerald,10,11,95,96oriental,85En cabochon-cut stones,64Experiments to show electric polarity,58,59Facets in stones, description of the,67,68Feminine stones,85Fire in stones (see also "Change of Colour," "Opalescence," and "Play of Colour"),36,37Fire opal,35Flame-coloured stones, list of,76Flaws,63Formation of precious stones,5,8chemical illustration of,8,9Garnet,11,100Garnets(A) iron-alumina (called also almandine and precious or oriental garnet),101sub-variety, common garnet,101(B) lime-iron,101sub-variety aplome,101melanite,101pyreneite,101topazolite,101(C) lime-chrome,101,102sub-variety uwarowite,101,102(D) lime-alumina,102sub-variety cinnamon stone,102romanzovite,102succinite,102(E) magnesia-alumina,102,103sub-variety carbuncle, or anthrax,102,103noble,103pyrope,102(F) manganese-alumina,103sub-variety spessartine, or spessartite,103Girdle portion of a stone,66Glimmering, in lustre, definition of,29Glinting, or glistening in lustre, definition of,29Goutte de suif-cut stones,65Great Mogul diamond,64Green stones, list of,78Groups of crystals (see "Crystals")Hardness, physical properties of,39table of,39,40,41Heat indexes,54physical properties of,52Hollow-cabochon,65Hyacinth, ordinary (a form of zircon),85,98oriental,85Hyalite (opal),35Hydrophane (opal),35Imitations and tests of precious stones,70Indigo sapphires,86Ink sapphires,85Iridescence, and cause of,37,38Iron-alumina garnets,101Jacinth, oriental,85Jarcon, or jargoon,98Koh-i-nûr,64Lapis-lazuli,103Light, physical properties of,26Lime-alumina garnets,102cinnamon stone,102romanzovite,102succinite,102Lime-chrome garnets,101,102uwarowite,101,102Lime-iron garnets,101aplome,101pyreneite,101topazolite,101List of stones according to colour,75-79hardness,39-41specific gravity,48-50Lustre,26,28Lustreless, definition of,29Lynx-eye stones,87Magnesia-alumina garnets,102,103carbuncle, or anthrax,102noble,103pyrope,102Magnetic and electric influences,57-61Malachite,11Manganese-alumina garnets,103spessartine, or spessartite,103Masculine stones,85Melanite,101Menilite (opal),36Metallic-lustre stones,28,29Mohs's table of hardness,39-41Noble garnet,103or precious opal,35Non-diaphanous stones,28Odontolite,106Olivine corundum (see "Chrysolite"),85Opal,11varieties of,35,36Opalescence (not to be confused with "Change of Colour" and "Play of Colour,"which see; see also "Fire"),36,37Oriental amethyst,85cat's eye (see "Cat's eye")emerald,85garnet,101topaz,85Origin of precious stones,7Paste, or strass, for imitation stones, composition of,71Pavilion portion of cut stones,66Pearly-lustre stones,28,29Peridot (see "Noble Chrysolite"),85Pink-coloured stones, list of (see also Red),77Pinked topaz,92Phosphorescence,26,30Physical properties:—A.—Crystalline structure,13B.—Cleavage,19C.—Light,26D.—Colour,32E.—Hardness,39F.—Specific gravity,45G.—Heat,52H.—Magnetic and electric influences,57Play of colour (not to be confused with "Change of Colour" and "Opalescence," which see; see also "Fire"),36,37Pleochroism,33Polarisation, electric,58,59of light,26,27Polariscope,27,28Polishing precious stones,3,4Polymorphism in precious stones,25Precious, or noble opal,35Pseudomorphism in precious stones,23,24Pyreneite,101Pyro-electricity, development and behaviour of,58-60Pyrope,102Qualities of precious stones,1,3Red and rose-coloured stones, list of (see also Pink),76,77Reflection of light,26,28Refraction of heat,52-55light,26,27Reproduction of crystalline form,20,21Resinous lustre stones,28,29Rock-crystal,11Romanzovite,102Rose-coloured stones (see Red, above),76,77Rose, or rosette-cut stones,65Rothschild's testing solution,73Ruby, characteristics of,83composition of,10Sapphire, amethyst,85and its varieties,84,85cleared,86diamonds,87indigo,86ink,85the blue, composition of,10,85water,86Semi-diaphanous stones,28Shining, in lustre, definition of,29Silica group, composition of the,11Silicates,100Silky-lustre stones,28,29Single-refraction (see "Refraction")South African diamond (see "Cullinan Diamond")Specific gravity,45Splendent, in lustre, definition of,29Splitting of the Cullinan diamond,22Star-portion of stones,65Stars of Africa (see also "Cullinan Diamond"),22,64,68Starting or splitting of stones on cleavage planes,23Step-cut stones,66Stones arranged according to colour,75-79hardness,39-41specific gravity,48-50Strass for imitation stones, composition of,71Sub-metallic in lustre, definition of,29Sub-translucent stones,28Sub-transparent stones,28Succinite,102Synthesis,5Systems of crystals (see "Crystals")Table-cut stones,65Tallow drops,65Teeth of stone,65Testing by crystalline structure,17hardness,40,43with needles,41gems by dichroscope,33,34solution (Rothschild's),73Tests of precious stones (general),70Topaz,11,91colours of, in dichroscope,34oriental,85Topazolite,101Tourmaline,96,97electric experiments with,58,59Translucent stones,28Transmission of heat,52-56light,26Transparent stones,28Trap-cut stones,66Tri-morphism in precious stones,25Triplets,72Turquoise,104(bone),106composition of the,11odontolite,106Uwarowite,101,102Violet stones, list of,78Vitreous-lustre stones,28,29Water-sapphires,86White (paste) stones,71stones, list of,75Yellow stones, list of,76topaz,92Zircon,10,98diamonds,99Zirconium,10
LONDON: PRINTED BY WILLIAM CLOWES AND SONS, LIMITED,GREAT WINDMILL STREET, W., AND DUKE STREET, STAMFORD STREET, S. E.