The cleaving and cutting and polishing of the Cullinan diamond was entrusted to the firm of Asscher and Co., in Amsterdam. The cleavage of the diamond was very successfully accomplished by Mr. Joseph Asscher. An incision half an inch deep was made with a sharp diamond point in the proper place, then a specially designed knife blade was placed in the incision and it was struck a heavy blow with a piece of steel. The diamond split through a defective spot, part of which was left in each portion of the diamond. Gigantic as is the Cullinan diamond, it represents in weight less than half the daily output of the De Beers mines, which averages about 7000 carats per day. Next in size to the Cullinan comes the one which was found at the Jagersfontein Mine. It weighed 970 carats--over half a pound. The following table gives the names and weights of some historic diamonds (Fig. 13): 1. Koh-i-noor, after the second cutting, 106 carats. 2. Loterie d’Angleterre, 49 carats. 3. Nizam of Hyderabad, 279 carats. 4. Orloff, 194 carats. 5. Koh-i-noor, after first cutting, 279 carats. 6. Regent or Pitt, 137 carats. 7. Duke of Tuscany, 133 carats. 8. Star of the South, 124 carats. 9. Pole Star, 40 carats. 10. Tiffany, yellow, 125 carats. 11. Hope, blue diamond, 44 carats. 12. Sancy, 53 carats. 13. Empress Eugenie, 51 carats. 14. Shah, 86 carats. 15. Nassak, 79 carats. 16. Pasha of Egypt, 40 carats. 17. Cullinan, 3025 carats. 18. Excelsior, Jagersfontein, 969 carats. [Illustration: FIG. 13. SOME HISTORIC DIAMONDS. To face p. 80.] CHAPTER VII BOART, CARBONADO, AND GRAPHITE The black inclusions in some transparent diamonds consist of graphite. On crushing a clear diamond showing such spots and heating in oxygen to a temperature well below the point at which diamond begins to burn, Moissan found that the grey tint of the powder disappeared, no black spots being seen under the microscope. There also occur what may be considered intermediate forms between the well-crystallised diamond and graphite. These are “boart” and “carbonado.” Boart is an imperfectly crystallised diamond, having no clear portions, and therefore useless for gems. Shot boart is frequently found in spherical globules, and may be of all colours. Ordinary boart is so hard that it is used in rock-drilling, and when crushed it is employed for cutting and polishing other stones. Carbonado is the Brazilian term for a still less perfectly crystallised form of carbon. It is equally hard, and occurs in porous masses and in massive black pebbles, sometimes weighing two or more ounces.