Under atmospheric influences the iron would rapidly oxidise and rust away, colouring the adjacent soil with red oxide of iron. The meteoric diamonds would be unaffected and left on the surface of the soil, to be found haphazard when oxidation had removed the last proof of their celestial origin. That there are still lumps of iron left at Arizona is merely due to the extreme dryness of the climate and the comparatively short time that the iron has been on our planet. We are here witnesses to the course of an event which may have happened in geologic times anywhere on the earth’s surface.
Although in Arizona diamonds have fallen from the skies, confounding our senses, this descent of precious stones is what may be called a freak of nature rather than a normal occurrence. To the modern student of science there is no great difference between the composition of our earth and that of extra-terrestrial masses. The mineral peridot is a constant extra-terrestrial visitor, present in most meteorites. And yet no one doubts that peridot is also a true constituent of rocks formed on this earth. The spectroscope reveals that the elementary composition of the stars and the earth are pretty much the same; and the spectroscope also shows that meteorites have as much of earth as of heaven in their composition. Indeed, not only are the selfsame elements present in meteorites, but they are combined in the same way to form the same minerals as in the crust of the earth.
It is certain from observations I have made, corroborated by experience gained in the laboratory, that iron at a high temperature and under great pressure—conditions existent at great depths below the surface of the earth—acts as the long-sought solvent for carbon, and will allow it to crystallise out in the form of diamond. But it is also certain, from the evidence afforded by the Arizona and other meteorites, that similar conditions have existed among bodies in space, and that on more than one occasion a meteorite freighted with jewels has fallen as a star from the sky.
INDEX
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
W. BRENDON AND SON, LTD., PRINTERS, PLYMOUTH