lavasten

Lavasten is a term used in several Nordic languages for lava stone, a rock formed from solidified magma that erupts onto the Earth’s surface. It covers a range of volcanic rocks that originate from lava cooled at or near the surface.

Formation and texture: Lava stone is an extrusive igneous rock produced when magma erupts as lava and rapidly cools. The fast cooling yields fine-grained textures such as basalt, and in some cases glassy or vesicular textures as seen in obsidian or pumice. Common varieties include basalt and andesite (mafic), rhyolite and obsidian (felsic to intermediate), and pumice (highly vesicular).

Composition and properties: Lava stones typically consist of silicate minerals like plagioclase, pyroxene, olivine, and quartz in varying proportions. They can be dense and durable (basalts) or light and porous (pumice). The color ranges from dark gray to black, with lighter hues in felsic varieties; weathering and oxidation can impart red or brown tints.

Uses: Due to durability or porosity, lava stone is used as construction material (basalt tiles, paving stones), in landscaping and architecture, and as decorative objects or jewelry from glassy forms like obsidian. Pumice is widely used as an abrasive in industry.

Occurrence: Lava stones occur wherever lava flows reach the surface—oceanic ridges, volcanic islands, hot spots, and volcanic arcs. Notable regions include Iceland and other basalt-rich areas of the North Atlantic, Hawaii, and parts of Italy and East Africa.