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INDEX
113
PAGE
Rock-crystal ......... 11
Romanzovite ......... 102
Rose-coloured stones (see Red, above) . . . 76,77
Rose, or rosette-cut stones ....... 65
Rothschild's testing solution . . . . . .73
Ruby, characteristics of . . . . . .83
,, composition of . . . . . . .10
Sapphire. amethyst ........ 85
mid its varieties ..... 84,85
cleared ........ 86
diamonds . . . . . . .87
indigo ........ 86
..ink.........85
the blue, composition of . . . . 10,85
,. water ........ 86
Semi-diaphanous stones ....... 28
Shining, in lustre, definition of. . .. . . .29
Silica group, composition of the . ..... 11
Silicates..........100
Silky-lustre stones.......28, 29
Single-refraction (see '" Refraction ")
South African diamond (see " Cullinan Diamond ")
Specific gravity ........ 45
Splendent, in lustre, definition of . . . .29
Splitting of the Cullman diamond ..... 22
Star-portion of stones ....... 65
Stars of Africa (sec also•' Cullinan Diamond ") . . 22, 64, 68
Starting or splitting of stones on cleavage planes. . . 23
Step-cat stones ........ 66
Stones arranged according to colour .... 75-79
„ „ hardness . . 39-41
„ ., specific gravity . . 48-50
Stress for imitation stones, composition of . . .71
Sub-metallic in lustre, definition of . . .29
Sub-translucent stones . . . . . . .28
Sub-transparent stones ....... 28
Succinite ...... . . 102
Synthesis ......... 5
Systems of crystals (see " Crystals ")
Table-out stones ........ 65
Tallow drops ......... 65
Teeth of stones ........ 65
Testing by crystalline structure ..... 17
hardness.......40, 43
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