Two types of diamond

Abstract

Among a number of diamonds supplied to us by Professor W. T. Gordon, of King’s College, London, one, by a fortunate chance, was found to differ from the rest in its infra-red spectrum. Having confirmed by various methods th at a large absorption band at 8 g. present in the spectrum of all the other diamonds, was absent in this particular one, we explored photographically the ultra-violet spectrum of all the diamonds then available, and found th at the stone which was transparent at 8 p. in the infra-red was also transparent from about X 3000 to X 2250 in the ultra-violet, the other diamonds being opaque beyond X 3000. At this stage, between two and three hundred diamonds were examined visually by means of a simple ultra-violet spectroscope with fluorescent eye-piece without another diamond transparent beyond X 3000 being found. Among other physical and optical properties examined in comparison, little difference was found between diamonds of the usual and the transparent type : their waterwhiteness, density, refractive index, dielectric constant, Raman frequency and the earlier X-ray patterns appeared the same. A difference in the crystalline condition was, however, noted, for the transparent diamond was made up of a large number of parallel laminae, and it was also more nearly isotropic when examined by polarized light than the others.

Heats of combustion of diamond and of graphite

“…It has been reported by Robertson, Fox, and Martin [7] that there are two types of diamond which differ in a number of physical properties, and it is conceivable that one of the samples in the present work consisted largely of one of these types, while the other sample consisted largely of the other type of diamond. This is extremely unlikely, however, because of the comparative rarity of one of the types.…”

Incorporation of Large Impurity Atoms into the Diamond Crystal Lattice: EPR of Split-Vacancy Defects in Diamond

“…The directions are for a C 2h symmetry site with (1-10) as its plane of reflection symmetry. g 1 corresponds to (1)(2)(3)(4)(5)(6)(7)(8)(9)(10), and α is the angle between g 2 and <110>. NE2 has the C 1 symmetry, and g 1 is 20…”

“…• from (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). β is the angle between A 1 and <111>, A 3 corresponds to (1)(2)(3)(4)(5)(6)(7)(8)(9)(10).…”

“…Electron paramagnetic resonance (EPR) parameters for titanium-containing centers with S = 1/2 in diamond. g 1 (A 1 ) corresponds to (1)(2)(3)(4)(5)(6)(7)(8)(9)(10), α is the angle between g 2 (A 2 ) and (110). γ is the angle between A 1 and (1-1-1) or (-11-1) that rotates towards (1-10), A 2 is perpendicular to the (110) plane [32,33].…”

“…Robertson et al carried out an optical study of a large amount of different natural diamonds. Based on this study, they divided diamonds into two types: diamonds of different groups have different absorption spectra in infrared (IR) and ultraviolet (UV) ranges [2]. Mass spectrometry measurements of Kaiser and Bond [3] showed a large amount of a nitrogen impurity in diamond crystals of type I.…”