Lubjakivi

Lubjakivi is the Estonian term for limestone, a sedimentary rock composed mainly of the mineral calcite (calcium carbonate, CaCO3). Limestone forms primarily from the accumulation and lithification of calcareous skeletal remains of marine organisms, such as shells and corals, or by chemical precipitation of calcium carbonate from water. It commonly contains fossils and impurities such as clay, silica or iron oxides, which influence its color and texture.

Depending on origin, limestone textures range from fine-grained to coarse, with textures including fossiliferous, oolitic, and crystalline varieties. Some limestone is biogenic, others chemical or detrital. Dolostone is a related rock in which magnesium replaces some calcium; these are sometimes grouped with limestone in common language but differ geologically.

Calcite-rich limestone effervesces with dilute acid (fizzing) and has a Mohs hardness around 3 to 4. It is typically porous and weatherable, with color ranging from white to gray, yellow, or brown depending on impurities.

Limestone is widely used as a building stone and as a raw material for lime production and cement. It is also ground into agricultural lime to improve soil pH and used in various industrial applications, including iron and steel production and as filler in plastics and paints.

Limestone occurs in many regions around the world, including Europe where extensive deposits are quarried for construction and industrial uses. In Estonia, as in neighbouring areas, limestone has historically supported quarrying and lime burning, shaping local architecture and rural landscapes.