Nickel diopside

Fig. 1. An indicator mineral plume consisting of Cr-diopsides glacially dispersed from the Thompson Nickel Belt in Manitoba, Canada, detected in 20 litre till samples at a 30-km spacing (Thorleifson et al. 1994 Thorleifson Matile 1997). 

Lindstrom D. I and Weill D. F. (1978). Partitioning of transition metals between diopside and coexisting silicate liquids, I Nickel, cobalt, and manganese. Geochim. Cosmochim. Acta, 42 801-816. 

The amoeboid descriptor for amoeboid olivine aggregates refers to their irregular shapes. AOAs tend to be fine-grained and porous, and have comparable sizes to CAIs in the same meteorite. They consist mostly of forsterite and lesser amounts of iron-nickel metal, with a refractory component composed of anorthite, spinel, aluminum-rich diopside, and rarely melilite. The refractory component is sometimes recognizable as a CAI embedded within the AOA. The AOAs show no evidence of having been melted, but some contain CAIs that have melted. 

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