Models for a xenocryst origin for kimberlite olivines emphasise the similarity between their core compositions and those in mantle peridotites. While this permits a xenocryst origin, it does not provide proof, as magmas generated in equilibrium with mantle olivines could, in principle, crystallize initial olivines matching those in the source region. Further, in several kimberlites, there is a striking disparity between the compositional range of olivine cores and that in associated mantle peridotite xenoliths from the same locality. Olivine-liquid Mg-Fe exchange coefficients and Ni partition coefficients permit equilibrium between Mg-rich mantle olivines (Mg # ~ 94–93) and magmas matching kimberlite bulk rock compositions. Glass inclusions in olivine megacrysts from the Monastery kimberlite, with compositions which overlap the range of archetypal Group I kimberlites, were interpreted to represent original liquids trapped at pressures of 4.5–6 GPa. These glass inclusions provide direct petrographic support for primitive melts matching kimberlite bulk chemistry in the lower SCLM.

A majority of kimberlitic olivines show normal (decreasing Mg #) core to rim zonation. Cores of normal-zoned kimberlitic olivines are typically homogeneous, but collectively define a field with a range in Mg # and invariant or slightly decreasing Ni towards more Fe-rich compositions. The most Mg-rich cores of normal-zoned olivines typically have Mg # in the range 94–93, but there are marked differences in the Fe-rich extreme of the normal-zoned population between different kimberlite clusters. Olivine rims typically define a field characterized by steeply decreasing Ni, coupled with invariant or slightly increasing or decreasing Mg #, which invariably overlaps the Fe-extreme of core compositions of the relatively Mg-rich, normal-zoned olivines. Consequently, while there is a sharp inflection in chemical gradient between the respective fields of cores and rims, they nevertheless define a continuous compositional field. Trace element modelling demonstrates that these zonation patterns can be explained in terms of a Raleigh crystallization model.

Most, if not all kimberlites are characterized by a subordinate group of olivine macrocrysts with cores that are Fe-rich relative to the field for rims, and thus show reverse zonation, which are interpreted to be linked to the Cr-poor megacryst suite. Rare Mg-rich olivines (relative to rims), have high-pressure inclusions of garnet, clinopyroxene and orthopyroxene. When present, such inclusions often show disequilibrium features such as internal chemical zonation. This points to a very short mantle residence time prior to entrainment by the host kimberlite, indicating a link to the Cr-rich megacryst suite rather than mantle peridotites. In addition to a variable, but generally subordinate proportion of olivines derived from Cr-poor and Cr-rich megacrysts, xenocrysts derived from disaggregated mantle peridotites will undoubtedly be present. While their proportions are difficult to quantify, the collective evidence points to a cognate origin for a majority of kimberlitic olivines. A kimberlite magma ascent model is proposed which provides a framework for understanding both olivine compositional variation and apparently enigmatic internal and external olivine morphology.

金伯利岩橄榄石的异晶起源模型强调了它们的核心成分与地幔橄榄岩中的成分之间的相似性。虽然这允许异种水晶起源，但它没有提供证据，因为与地幔橄榄石平衡产生的岩浆原则上可以结晶与源区中的橄榄石相匹配的初始橄榄石。此外，在几个金伯利岩中，橄榄石核的组成范围与来自同一地点的相关地幔橄榄岩包体的组成范围存在显着差异。橄榄石-液体 Mg-Fe 交换系数和 Ni 分配系数允许富镁地幔橄榄石（Mg # ~ 94-93）和与金伯利岩块状岩石成分相匹配的岩浆之间达到平衡。Monastery 金伯利岩橄榄石巨晶中的玻璃包裹体，其成分与原型 I 组金伯利岩的范围重叠，被解释为代表在 4.5-6 GPa 压力下捕获的原始液体。

大多数金伯利岩橄榄石显示出正常（减少 Mg #）的核到边缘分带。正常带金伯利岩橄榄石的核心通常是均质的，但共同定义了一个范围在 Mg # 和不变或略微减少 Ni 到更富含 Fe 的成分的领域。正常带橄榄石中最富镁的核心通常具有 94-93 范围内的 Mg #，但不同金伯利岩簇之间正常带族群的富铁极端存在显着差异。橄榄石边缘通常定义了一个以 Ni 急剧下降为特征的场，同时伴随着不变或略微增加或减少的 Mg #，它总是与相对富镁、正区橄榄石的核心成分的 Fe 极端重叠。最后，虽然核心和边缘的各自领域之间的化学梯度存在急剧变化，但它们仍然定义了一个连续的组成领域。微量元素建模表明这些分带模式可以用 Raleigh 结晶模型来解释。

大多数（如果不是全部）金伯利岩的特征是一组下级橄榄石大晶，其核心相对于边缘区域富含铁，因此显示反向分带，被解释为与贫铬巨晶组有关。稀有的富镁橄榄石（相对于边缘）具有石榴石、单斜辉石和斜辉石的高压包裹体。当存在时，此类包裹体通常表现出不平衡特征，例如内部化学分带。这表明在被寄主金伯利岩夹带之前地幔停留时间非常短，表明与富含铬的巨晶组而不是地幔橄榄岩有关。除了来自贫铬和富铬巨晶的橄榄石的可变但通常次要比例外，无疑会存在来自分解地幔橄榄岩的异晶。虽然它们的比例难以量化，但集体证据表明，大多数金伯利岩橄榄石都有同源来源。提出了金伯利岩岩浆上升模型，该模型为理解橄榄石成分变化和明显神秘的内部和外部橄榄石形态提供了框架。