Andesite

Andesite is a type of igneous rock.

Polished andesite is the polished version of andesite.

Natural generation
One block of polished andesite can be found in igloo basements. Polished andesite can also be found in the "nature", "blacksmith", and "large jail" rooms of woodland mansions.

Andesite generates naturally in coral reefs, replacing some coral as part of coral crusts.‌ [Bedrock Edition only]

Mineral veins
Andesite can generate in the Overworld in the form of mineral veins. Andesite attempts to generate 10 times per chunk in veins of size 33, from altitudes 0 to 80, in all biomes.

ID
Java Edition: Bedrock Edition:

Block data
See also: Data values

In Bedrock Edition, andesite uses the following data values

Issues
Issues relating to "Andesite" or "Polished Andesite" are maintained on the bug tracker. Report issues there.

Trivia

 * In real life, andesite is an extrusive igneous rock, meaning that it is formed from magma (thus igneous) that had flowed out to the surface (thus extrusive) as lava and cooled down.
 * Andesite's intrusive counterpart is diorite, meaning that diorite and andesite are made of the same materials but diorite formed inside the earth instead of flowing out.
 * In other words, andesite is rock formed from cooled lava, and diorite is rock formed from cooled magma.