196 Diamond

Figure 9.21. Micro-diamond photographed under an ultra-violet filter of 2250 Å. The transparent crystals are Type II; the opaque ones are Type I. There is no difference in morphology between the two. Note the high proportion of Type II crystals. In macrodiamond, the ratio is much lower because the Type I and II layers are alternately stacked.

of Type II crystals appeared in the ascending process from the Earth’s depth to the surface, and not during the mining process.

In the morphology of as-grown micro-diamond crystals, no essential difference was detected between Type I and II crystals, which both take octahedral forms. This is clearly shown in Fig. 9.21 [21], in which the two types are compared by the transmittance of ultra-violet rays. There is no essential difference in morphology between Type II, which is transparent under the ultra-violet ray used, and Type I, which is opaque to the same wavelength.

References

1V. Goldschmidt, Atlas der Kristallformen, B.I–B.IX, Heidelberg, Carl Winters Universitatsbuchhandlung, 1913–23

2 M. Seal, Structure in diamond as revealed by etching, Am. Min., 50, 1965, 105–23

3C. V. Raman and S. Ramaseshan, The crystal forms of diamond and their significance,

Proc. Ind. Acad. Sci., A24, 1946, 1–24

4 A. Fersman and V. Goldschmidt, Der Diamant, Heidelberg, Winter, 1911

References and suggested reading 197

5 A. F. Williams, Genesis of the Diamond, London, Benn, 1932

6 S. Tolansky, The Microstructures of Diamond Surfaces, London, N. A. G. Press, 1955

7F. C. Frank, Defects in diamond, in Science and Technology of Industrial Diamonds, ed. J. Burls, London, IDIB, 1967, pp. 119–35

8H. Kanda, S. Yamaoka, N. Setaka, and H. Komatsu, Etching of diamond octahedron by high pressure water, J. Crystal Growth, 38, 1977, 1–7

9 E. S. Dana, The System of Mineralogy, 6th edn, New York, John Wiley & Sons, 1892–1915

10C. Palache, H. Berman, and C. Frondel, The System of Mineralogy, 7th edn, vol. 1, New York, John Wiley & Sons, 1944

11Yu. L. Orlov, The Mineralogy of The Diamond, New York, John Wiley, 1977

12I. Sunagawa, K. Tsukamoto, and T. Yasuda, Surface microtopographic and X-ray topographic study of octahedral crystals of natural diamond from Siberia, in Materials Science of the Earth’s Interior, ed. I. Sunagawa, Dordrecht, D. Reidel, 1984

13M. Arima, Experimental study of growth and resorption of diamond in kimberlitic melts at high pressures and temperatures, in Advanced Materials ’96, Tsukuba, NIRIM, 1996, pp. 223–8

14H. Yamaoka, M. Akaishi, and S. Yamaoka, Diamond formation in the graphite-MgO-H2O system, Advanced Materials ’96, Tsukuba, NIRIM, 1996, pp. 245–50

15I. Sunagawa, The distinction of natural from synthetic diamonds, J. Gemmol., 24, 1995, 489–99

16F. C. Frank and A. R. Lang, X-ray topography of diamond, in Physical Properties of Diamond, ed. R. Berman, Oxford, Clarendon Press, 1965, pp. 69–115

17A. R. Lang, Internal structure, in The Properties of Diamond, ed. J. E. Field, London, Academic Press, 1979, pp. 425–69

18I. Sunagawa, T. Yasuda, and H. Fukushima, Fingerprinting of two diamonds cut from the same rough, Gem and Gemmology, Winter Issue, 1998, 270–80

19I. Sunagawa, A discussion on the origin of irregular shapes of Type II diamonds,

J. Gemmol., 27, 2001, 417–25

20M. Takagi and A. R. Lang, X-ray Bragg reflexion, “spike” and ultra-violet adsorption topography of diamonds, Proc. Roy. Soc., A 281, 1964, 310–22

21S. Tolansky and H. Komatsu, Abundance of type II diamonds, Science, 157, 1967, 1173–5

Suggested reading

I.Sunagawa, Talks on Diamond, Tokyo, Iwanami Pub. Co., 1964 (in Japanese)

R.Berman (ed.), Physical Properties of Diamond, Oxford, Clarendon Press, 1965

J.Burls (ed.), Science and Technology of Industrial Diamond, London, IDIB, 1967

I.Sunagawa, Diamonds, Their Genesis and Properties, Tokyo, Ratis, 1969 (in Japanese) Yu. L. Orlov, The Mineralogy of The Diamond, New York, John Wiley, 1977

J.E. Field (ed.), The Properties of Diamond, London, Academic Press, 1979

E. Wilks and J. Wilks, Properties and Applications of Diamonds, London, Butterworth-

Heinemann, 1991

J. E. Field (ed.), The Properties of Natural and Synthetic Diamond, London, Academic Press,

1992