PAGE
Cullinan
diamond (see also " Stars of Africa ") . 22, 64, 68, 80 Cutting of
precious stones. . . . . 3, 4, 62
Cymophane ......... 90
Definition' of a precious stone ...... 1
Diamond, characteristics of the ...... 80
composition of the . . . . . .10
., (sapphire) ....... 86
unique ........ 10
,. (zircon) ........ 19
Diaphaneity........ 20, 28
Diaphanous stones ........ 28
Dichroscope ......... 33
„ how to make a ...... 33
., how to use a . . . . . . .34
Dimorphism in precious stones ...... 25
Double cabocliou-cut stones ...... 65
., refraction (see '• Refraction ") Doublets.........72
Electric and magnetic influences ..... 57
experiments with precious stones and pithball and electroscope ....... 57
experiments with tourmaline ... 58. 59
Emerald........10, 11. 95, 96
., oriental ........ 85
En cabuchon-cut stones ....... 04
Experiments to show electric polarity . . . 58. 59
Facets in stones, description of the .... 67, 68
Feminine stones ........ 85
Fire in stones (see also '• Change of Colour," " Opalescence."
and - Play of Colour ") ..... 36, 37
Fire opal.........35
Flame-coloured stones, list of . . . . . . 76
Flaws..........63
Formation of precious stones . . . . . . 5, 8
., .. .. chemical illustration of . . 8. 9
Garnet.........11, 100
Garnets (A) iron-alumina (called also almandine and precious
or oriental garnet) . . . 101 sub-variety, common garnet . 101
