English: Kimberlite from the Devonian of Russia.

This kimberlite sample is from an exploratory drill core in a diamondiferous pipe in northwestern Russia.

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Sample description by a Russian diamond exploration geologist (I'm not 100% sure who it was):

Kimberlite xenotufobreccia (Kimberlite xenotuff breccia), Pionerskaya Pipe, Zolotitskoye Field.

Structure is lithocrystalloclastic. The quantity of fragments is about 90% of rock volume. Composition of fragments: 15% - clastogene quartz, 20% - kimberlites, fragments of crystals of olivine, rare crystalloclasts of chloritized phlogopite, 55% - xenogenic lithoclasts represented by argillites, aleurolites, carbonaceous rocks. Sizes of fragments of olivine are 0.1-1.5 millimeters, quartz up to 0.2-0.4 millimeters, fragments of kimberlites up to 1.5-3 millimeters. Cemented mass of xenotufobreccia has saponite-serpentine composition and it is characterized by increased content of limonite. Among accessory minerals there are predominant high chromium chrome-spinellids, which predominate over pyropes and chrome-diopsides.

[Note: the Russian term "aleurolite" is close in meaning to siltstone. "Argillite" probably means shale, not the very low-grade metamorphic rock.]

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Geologic unit: Pionerskaya Pipe, Zolotitskoye Field, Arkhangelskaya Diamond Province, Late Devonian

Locality: Pionerskaya Pipe, north-northeast of the town of Arkhangelsk, Arkhangelsk Region, east of the White Sea, northwestern Russia