Karkeakivi

Karkeakivi is a type of igneous rock that is primarily composed of the mineral olivine. It is a dark-colored rock, typically greenish-black, and is often found in volcanic areas. The name "karkeakivi" is derived from the Finnish language, where "karkea" means rough or coarse, and "kivi" means stone, reflecting the rock's rough texture.

Karkeakivi is formed from the rapid cooling of magma or lava, which prevents the formation of large crystals. This results in a fine-grained or glassy texture. The rock is often associated with basaltic magma, which is rich in iron and magnesium. The presence of olivine gives karkeakivi its distinctive greenish color, which can vary depending on the amount of iron present.

Karkeakivi is commonly used as a building material in construction due to its durability and resistance to weathering. It is also used in the production of aggregates for road construction and as a source of olivine for various industrial applications. The rock's rough texture makes it suitable for use as a grinding material in abrasive tools.

Karkeakivi is found in various locations around the world, including Finland, where it is a significant component of the country's geology. It is also found in other volcanic regions, such as Iceland and Hawaii. The rock's presence in these areas is a result of volcanic activity, which has shaped the landscape and contributed to the formation of karkeakivi.