Amethyst geode



Amethyst geodes are common underground structures which serve as the only source of amethyst items and blocks, tuff, and calcite.

Generation
Amethyst geodes generate underground anywhere between sea level and bedrock regardless of whether or not "Generate Structures" is toggled off for said world. It is possible that they can even break bedrock upon spawning. It overrides cave and ravine generation and abandoned mineshafts as well as other structures but sometimes can be overridden by other structures. In some cases, amethyst geodes can sometimes generate exposed on the surface, such as on beaches and underwater in oceans, but can be also found exposed in any biome if the geode is below Y=70.

Structure
Amethyst geodes consist of three layers: an outer layer of tuff, a middle layer of calcite, and a hollow layer of amethyst blocks with budding amethyst blocks randomly generated throughout. Amethyst crystals generate within the structure on budding amethyst. Surrounding the amethyst is a shell of calcite, which itself is surrounded by a shell of tuff. Geodes have a 95% chance of generating with a crack, exposing its inside. Caves cannot cut into geodes, and as such are often obstructed by them, except in cases where the crack intersects a cave.

Trivia

 * The shape and layers of an amethyst geode are similar to those of a real world amethyst geode.