Encyclopedy Index
Rapakivi
granite is a hornblende-biotite
granite containing large rounded crystals of
orthoclase mantled with oligoclase. The name has come to be used most frequently as a textural term where it implies
plagioclase rims around
orthoclase in plutonic rocks. Rapakivi is Finnish for rotten or crumbly rock and describes the tendency of the rapakivi
granite to easily weather.
Rapakivi is a fairly uncommon type of
granite, mostly found in southeastern Finland. It can also be found e.g. on Åland, in Laitila in southwestern Finland, and in some parts of Sweden.
Rapakivi is the material used in Ålands Middle Age stone churches.
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