212 THE CULLINAN DIAMOND. 



DESCRIPTION OF THE SURFACES. 



A is an original octahedral face shoAving typical striations, the 

 bands varying from ()-l to 4 centimeter, and running parallel to the 

 edge AE. 



B is a large surface slightly curved showing partial striations, 

 which, however, are interrupted by the slightly mammillary character 

 of the surface. 



C is also a natural surface showing a few striations parallel to the 

 edge CE. 



D. Between B and F, C, G there is an irregular octahedral face, 

 I), sliowing distinct equilateral triangular indentations which resem- 

 ble etched figures, except in regard to their 

 comparatively large size, the largest having a 

 side measuring 0*7 centimeter. D is parallel 

 to PI 



E, F, G, H are cleavage planes. 



E is the largest of these, and is a very per- 



'?ct cleavage plane. Parallel to it within the 



crystal there is a small air layer between tw^o 



internal cleavages, producing a " rainbow," or 



Newton's rings. 



F is the second largest of the cleavage 

 planes and shows a small spot w^ithin the 

 crystal. 

 i)iagra.aniatic projection (to (t is an irregularly shaped cleavage plane. 



half scale). j-j [q another cleavage face showing series 



of cleavages in the corner bounded by E and G. Two spots are 

 visible, one actually on the surface, the other about 1 centimeter 

 Avithin the ciystal. 



Of the faces given, A and G, H and B, and E and D are parallel. 

 In the case of B and H the parallelism is imperfect owing to the 

 curvature of B. 



The purity of the crystal is best seen on looking into face E, and 

 the luster is w^ell seen on the irregular natural face B, the broken 

 cleavage on H causing a good deal of refraction, which affects B to 

 some extent as the facets of a cut gem would. For a large stone 

 the crystal is of remarkable purity, and the color approximates to 

 that of a blue-Avhite. 



The large size of the cleavage planes E and F indicates that a 

 very considerable portion of the crystal is wanting. From the shape 

 of B, D, and G, one can say that the entire crystal was irregular in 

 shape, but A and D being octahedral faces, the presumption is that 

 the complete crystal was a distorted octahedron, probably with dodec- 

 ahedral faces developed on the edges. The portions missing prob- 

 ably amount to more than half of the original crvstal. 



