KOIDU KIMBERLITE
Here's a bluish-green kimberlite sample from Sierra Leone in West Africa. It is from the diamondiferous Koidu Kimberlite Complex of Jurassic age. This particular specimen was collected in the 1970s or 1980s and comes from the Yengema-Koidu (Sefadu) area in eastern Sierra Leone. The rounded, light-green colored grains in the kimberlite are serpentinized olivine crystals having a mesh texture (reticulate texture) (just discernible in the photos below). This rock is apparently from one of the kimberlite dikes in the area (Dike Zone B, C, or D of Tompkins & Haggerty, 1984).
Location: approximately 8° ~35-40' North, ~11° West.
Above & below: Koidu Kimberlite sample. Large rounded serpentinized olivine grain at upper left (photo above) & ~center (photo below) is just over 4 mm in size.
Information mostly from Linda Tompkins (pers. comm.), Stuart McRae (pers. comm.), and Tompkins & Haggerty (1984, in Kimberlites I: kimberlites and related rocks, Proceedings of the "Third International Kimberlite Conference", volume 1. Developments in Petrology 11A.).