Andesite is a fine-grained igneous, volcanic rock, ranging in colour from brown and violet to grey.
Chemically, this rock predominantly consists of silicic acid (approximately 60%). Its formation temperature ranges between 950 -1000 oC, while the origin lava contains plagioclase, pyroxene, amphibole and biotite.
Bulk density: 2.6-2.8 t/m3
Water absorption capacity: 1.0 – 2.0 %
Compressive strength: 120-190 N/mm2 or 0.1cm2
MOHS hardness: 5-6
Freeze-thaw resistance: YES
Thanks to its technical characteristics, andesite is mainly used for outdoor works: pedestrian
footpaths and squares, paving of alleys and sidewalks, gardens, urban furniture.
Urban furniture made of andesite includes benches, pillars separating traffic areas, waste
storage containers, drains or even bike racks. It may also be used as blocks for tunnels and
foundations, paving blocks and kerbs for roads.
The largest andesite quarries are located in China, USA and Turkey. There are andesite
quarries in Romania as well, the most important being located in Pietroasa, Bihor County.