English: Skarn from Russia. (public display, Dakota Dinosaur Museum, Dickinson, North Dakota, USA)

Skarn is a contact metamorphic rock with a crystalline texture. It forms by heating and addition of elements (metasomatism) to country rock in the immediate vicinity of an igneous intrusion (batholith, stock, sill, dike, laccolith). The mineralogy of skarns is highly variable, depending on the chemistries of the host rock and the intruding magma.

I have not located any geologic information on this type of Russian skarn. I'm not sure the rock is even identified correctly by the museum. Its appearance is that of a travertine sample. Confirmatory or contradictory comments are welcome.

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From exhibit signage:

A thermally metamorphosed impure limestone. This stone was selected for extensive use in Moscow's subway stations.

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