Able, Sir F., closed vessel experiments, 122

Absorption spectrum of diamond, 101

Aliwal North, 6

Alluvial deposits of diamonds, 9

Amygdaloidal trap, 10

Arizona meteor, 136

Arkansas, diamonds in, 2

Ash of diamond, 82, 89

Augite, 20

Automatic diamond collector, 56


Barytes, 71
— density of, 93

Basalt, 15

Basutos, 12, 39

Bechuanas, 12, 39

Beryl, density of, 93
— refractive index of, 103

Biotite, 20

Blackening of diamonds, 98

Blue ground, 10, 47
— — diamantiferous, 18, 19

Boart, 81,
— combustion temperature of, 90
— density of, 93

Boiling-point of carbon, 110

Bonney, Rev. Professor, 67

Boyle on the diamond, 100

Brazil, diamonds in, 4

Breakwater, Cape Town, 36

Breccia, diamantiferous, 19

Brilliant cut diamond, 102

British Association in South Africa, 7

British Guiana, diamonds in, 4

Bronzite, 20, 71
— hydrated, 19

Bultfontein Mine, 14
— — characteristics of diamond from, 64

Bursting of diamonds, 105


Calcite, 20, 97

California, diamonds in, 3

Canada balsam, refractive index of, 103

Canyon Diablo meteorite, 136

Cape Colony, 5

Cape Town, 5

Carat, equivalent in grains, 69

Carbon, boiling and melting point of, 110
— combustion temperature of, 90
— critical point of, 110
— density of, 93
— dissolved in iron, 116
— volatilisation of, 115

Carbonado, 81
— density of, 93

Characteristics of diamonds from the different mines, 64

Chemical properties of diamond, 89

Chromate of lead, refractive index of, 103

Chrome diopside, 71
— iron, 20
— — ore, 71
— — — density of, 93

Chromite, 20

Classification of rough diamonds, 73

Cleavage of diamonds, 78

Coke, density of, 93

Colesberg Kopje, 26

Collecting the gems, 55

Coloured diamonds, 62, 82

Combustion of diamond, 89
— temperatures of diamond, boart, graphite, and carbon, 90

“Comet” crushers, 49

Compound system, 36, 37

Concentrating and washing machinery, 49

Convict labourers, 71

Cordite, diamond from explosion of, 123

Corundum, 20
— density of, 93

Cradock, 6

Craters or pipes, 18

Crown glass, refractive index of, 103

Crusher, “Comet,” 49

Crystallisation of diamond, 86

Crystals, octahedra, of diamond, 63, 86

Cullinan diamond, 15, 76, 80, 104


Dallas, Captain, 40

De Beers Consolidated Mines, 7, 33
— — floors at Kenilworth, 47
— — Mine, 14, 24, 34
— — — characteristics of diamonds from, 64
— — strong-room, 74

Delhi diamond, 107

Density of diamond, 57, 93
— of graphite, 83, 93
— of stones accompanying diamond, 70, 71, 93, 95

Depositing floors, 46

Dewar, Sir J., conversion of diamond into graphite, 123

Diabase, olivine, 16

Diallage, 20

Diamond, absorption spectrum of, 101
— and polarised light, 104
— a new formation of, 122
— ash of, 82, 89
— collector, automatic, 56
— combustion of, 89
— — temperature of, 90
— converted into graphite, 100
— density of, 57, 93
— etched by burning, 88
— explosion of, 120
— genesis of the, 115
— in meteors, 134
— in Röntgen rays, 107
— matrix of, 67
— natural formation of, 127
— Office at Kimberley, 73
— physical and chemical properties of, 89
— pipes or craters, 18
— radio-activity of, 109
— refractive index of, 103
— Trade Act, 36
— triangular markings on, 87
— tribo-luminescence of, 100

Diamonds, coloured or fancy, 62, 82
— Maskelyne on, 1
— noteworthy, 76
— phosphorescence of, 96
— produced, weight, value of, 35
— yield of, from De Beers, 60

Drift, diamonds from the, 12

Duke of Tuscany diamond, 80

Dutch boart, or zircon, 59

Dutoitspan Mine, 14, 23
— — characteristics of diamonds from, 64


Eclogite, 20
— containing diamonds, 67

Electrons, bombardment by, 98

Emerald, refractive index of, 103

Empress Eugenie diamond, 80

Enstatite, 20

Explosion of diamonds, 120

Excelsior diamond, 80


Fancy stones, 62

Fingoes, 39

Flint glass, refractive index of, 103

“Floating Reef,” 21

Floors, depositing, 46

Fluor-spar, refractive index of, 103

Formation, new, of diamond, 122

Fort Beaufort, 6

Franklinite, 97

Frank Smith Mine, 15
— — — characteristics of diamonds from, 66

Fraserburg, 6


Garnet, 20, 70
— density of, 93

Genesis of the diamond, 115

“Golden fancies,” 65

Granite, 18
— density of, 93

Graphite, 81, 83
— combustion temperature of, 90
— conversion of diamond into, 100
— density of, 93
— diamonds coated with, 99

Graphitic oxide, 83, 93

Grease, collecting diamonds by aid of, 57


Hard blue ground, 47

Hardness of diamond, 90

Haulage system, 46

Hexakis-octahedron crystal, 86

Hope blue diamond, the, 80

Hornblende, 71
— density of, 93


Iceland spar, refractive index of, 103

Ice, refractive index of, 103

I.D.B. laws (Illicit Diamond Buying), 36

Ilmenite, 20

India, diamonds in, 4

Inverel diamonds, 91

Internal strain in diamonds, 104

Iron a solvent for carbon, 116
— ore, density of, 93
— pyrites, 20


Jagersfontein diamond, 79
— Mine, 14
— — characteristics of diamonds from, 68

Jeffreysite, 20


Kafirs, 42

Kamfersdam Mine, 15
— — characteristics of diamonds from, 66

Kenilworth depositing floors, 47

Kimberley, 6
— blue ground, 10
— mines, 14, 23, 34
— Mine in old days, 25
— — at the present day, 34
— — characteristics of diamonds from, 63
— shales, 15
— West Mine, 15
— — — characteristics of diamonds from, 66

Kirsten’s automatic diamond collector, 57

Klipdam, 8, 23

Koffyfontein Mine, 14

Koh-i-noor diamond, 80
— hardness of, 91

Kyanite, 20, 71


Lamp, ultra-violet, 97

Leicester Mine, 15, 23
— — characteristics of diamonds from, 67

Loterie d’Angleterre diamond, 80

Lustre of rough diamonds, 56


Machinery for washing and concentrating, 49

Macles, 86

Magnetite, 20, 71
— density of, 93

Maskelyne on diamonds, 1

Matabele, 12, 39

Matrix of diamond, 67

Melaphyre, 10, 16

Melting-point of carbon, 110

Meteor, Canyon Diablo, 136

Meteoric diamonds, 134

Meydenbauer on meteoric diamonds, 135

Mica, 20, 71
— density of, 93

Moissan’s experiments on the genesis of diamond, 115

Mud volcano, 24


Nassak diamond, 80

Natal, coal in, 6

Natural formation of diamond, 127

Newlands Mine, 15
— — characteristics of diamonds from, 67

New Rush diggings, 26

Nizam of Hyderabad diamond, 80

Noble, Sir A., experiments, 122, 131

Noteworthy diamonds, 76


Octahedral crystals of diamond, 63, 86

Olivine, 20
— diabase, 16

Orange River Colony, coal in, 6
— — — diamonds in, 14

Orloff diamond, 80


Pasha of Egypt diamond, 80

Paterson, Mr., description of Kimberley in old days, 25

Peridot, 20, 139

Peridotite, 3

Perofskite, 20

Phosphorescence of diamonds, 96

Phosphorus, refractive index of, 103

Physical properties of diamond, 89

Picking tables, 51

Pipes or craters, 18

Pitt diamond, 80

Polarised light and diamond, 104

Pole Star diamond, 80

Pondos, 39, 42

Premier Mine, 15, 76

Prodigious diamonds, 76

Pseudobrookite, 20

Pulsator, 52

Pyrope, 70


Quartzite, 16, 20
— density of, 93
— refractive index of, 103


Radio-activity of diamond, 109

Radium, action on diamond, 108

“Reef,” 21

Refractive indices, 103

Refractivity of diamond, 102

Regent diamond, 80

Reunert, Mr., description of Kimberley Mine, 30

Rhodes, Cecil John, 34

River washings, 7

Rock shafts, 43

Röntgen rays, diamond in, 107

Ruby, refractive index of, 103

Rutile, 20


Sahlite, 20

Sancy diamond, 80

Savings of the native workmen, 41

Scalenohedron diamond crystal, 86

Serpentine, 19

Shafts, rock, 43

Shah diamond, 80

Shales, Kimberley, 15

Shangains, 39

Shells in blue ground, 21

Shot boart, 81

Silver and thallium, nitrate of, 94

Smaragdite, 20

Soft blue ground, 47

Sorting the diamantiferous gravel, 55

Specific gravity, see Density

Spectrum, absorption of diamond, 101

Sphalerite, 100

Spinthariscope, 108

Sprat’s History of the Royal Society, 1

Sprouting graphite, 84

Star of the South diamond, 80

Stones other than diamonds, 70, 71, 93, 95

Strain, internal, in diamonds, 104

Sulphur, refractive index of, 103

Swazis, 39


Ultra-violet lamp to show phosphorescence, 97

Underground workings, 43

United States, diamonds in, 2


Vaalite, 20

Vaal River, 8, 16

Valuators, 73

Value of diamonds per carat, 12, 69

Value of diamonds, progressive increase in, 69

Vermiculite, 20

Volatilisation of carbon, 115

Volcanic necks, 18

Volcano, mud, 24


Wages, scale of, 35

Washing and concentrating machinery, 49

Wesselton Mine, 14, 15, 23, 35
— — characteristics of diamonds from, 65

Willemite, 97

Wollastonite, 20

Workings, underground, 43


Yellow ground, diamantiferous, 19

Yield of diamonds, annual, 60
— — — total, 35
— falls off with depth, 68
— per load of blue ground, 62


Zimbabwe ruins, 40

Zircon, 20, 59, 71
— density of, 93

Zulus, 12, 39, 40