The principal aim of the present study has been to provide as comprehensive a picture as possible of the truly unique São Luiz diamonds, and has necessitated the employment of a wide variety of analytical techniques. In addition, the present work attempts to provide a synthesis and interpretation of all contemporary knowledge of both São Luiz material and deep mantle diamonds in general.

This philosophy has resulted in a rather unconventional research plan. The bulk of the study involves work directly undertaken by myself; diamond break-out, sample preparation, electron probe and ion microprobe analysis, Fourier transform Infra-Red spectroscopy, some X-Ray diffraction, some scanning electron microscopy, bulk d ¹³C analyses. In addition, a number of lines of enquiry have been followed by specialists in particular analytical techniques and wherever possible, an active part in this work has been undertaken by myself. These specialists include McCammon (Bayreuth, Mössbauer), Hursthouse and Light (ESPRC, Cardiff, XRD), Parsons, Gould and Blake (Edinburgh, Chemistry, XRD), Cartigny (Paris, d ¹⁵N and d ¹³C analysis), Conrad and Hemley (Carnegie Institution, Washington, XRD), Angel and Ross (UCL, FTIR and XRD), Rogerson (Edinburgh, SPM), Forsyth (Edinburgh, AFM), Findlay and Jeffreys (Edinburgh, SEM) and Condliffe (Leeds, SEM). This invaluable assistance is acknowledged, where appropriate, in the text.

In addition to presenting data from inclusions broken out by myself, many diagrams presented herein, involve published data from non-São Luiz sources and both published and unpublished data from São Luiz from previous work. Where this is the case, due attention is drawn. In addition, the thesis involves some work undertaken on a small number of lower mantle inclusions from Guinea; it is expected that this locality may be the next major source of deep seated diamonds available for study and, at present, further work is being undertaken by Stachel and Harris.