Extra reflexions from the two types of diamond

Abstract

New experimental facts about diamond, supported by X-ray photographs, are as follows: There are two kinds of extra reflexions to be seen on wellexposed Laue photographs. All diamonds show primary diffuse reflexions, which are temperature-sensitive but not structure-sensitive. These correspond to the diffuse reflexions observed under suitable conditions for all other substances. Type I diamonds, only, show the secondary reflexions (sharp spots, streaks and groups of spots) which have been previously described and which are not at all typical of diffuse spots in general. They are not really diffuse, they are not (or only slightly) temperature-sensitive and they are strongly structure-sensitive. Primary and secondary reflexions have been observed for many diamonds and in various orientations, associated with the {111} {220} {113} {331} Laue reflexions, using filtered and unfiltered radiation from copper andiron targets. There is as yet no explanation of the secondary reflexions which can account satisfactorily for the structure - sensitiveness, the presence of {220} spots, and the apparent incompleteness of the groups of spots actually observed.