Glendonite

Found at the mouth of the Olenitsa river between Umba and Kashkarantsy. Washed, cut in two pieces, and sold to foreigners as souvenirs.

        

Apparently this thing is also present in Australia near Glendon Brook too, thus the name. Details coming up later but from what I recall there is a souvenir store in Umba (south edge of Kola) where it is sold both whole and cut/polished.