diabaasikivistä

Diabaasikivet, also known as diabase or dolerite, are common intrusive igneous rocks. They are characterized by their fine-grained, dark-colored appearance and a composition typically rich in plagioclase feldspar and pyroxene. Diabaasikivet form when molten magma cools relatively slowly beneath the Earth's surface, but not slowly enough for large crystals to form. This results in a texture where individual mineral grains are often too small to be seen with the naked eye, a texture known as ophitic or subophitic.

These rocks are prevalent in various geological settings, often appearing as dikes, sills, or laccoliths, which are intrusions that cut across or lie parallel to existing rock layers. The widespread distribution of diabaasikivet is a testament to their formation during significant volcanic and tectonic activity throughout Earth's history. They are particularly common in ancient continental crust and are found in many parts of the world.

Diabaasikivet are known for their durability and resistance to weathering, making them useful in construction and as aggregate for roads and concrete. Their dark color can vary from gray to black depending on the specific mineral content and the degree of alteration. In some regions, diabaasikivet have been quarried for building materials and decorative stone. Their geological occurrence and properties make them an important subject in the study of igneous petrology.