Abstract
Totally-enclosed inclusions of barite, biotite ＋ chlorite, chlorite ＋ biotite ＋ garnet, chlorite ＋ calcite, omphacite, pyrrhotite, and pyrrhotite ＋ chalcopyrite from well-crystallized African diamonds, and forsterite, enstatite, and quartz from well-crystallized Brazilian diamonds, have been identified by X-ray diffraction and microchemical analyses. Totally-enclosed included matter known to date is reviewed and interpreted as indicating a broad range in chemical and physical environments during natural diamond formation. The range of included matter is consistent with the Harris-Middlemost evolutionary model for kimberlites, which proposes deep magmatic origin and interaction with country rock and successive fractionations during ascension.
