Botryoidal

Botryoidal habit of gibbsite crystals

A botryoidal (/ˌbɒtriˈɔɪdəl/ BOT-ree-OY-dəl) texture or mineral habit, is one in which the mineral has an external form composed of many rounded segments, named for the Ancient Greek βότρυς (bótrus), meaning "a bunch of grapes".[1] This is a common form for many minerals, particularly hematite and malachite, which are known for frequently forming botryoidal masses. It is also a common form of goethite, smithsonite, fluorite, and chrysocolla.

Similar habits are reniform (kidney-shaped) and mammillary (breast-shaped or partial spheres).

  1. ^ Adjective form: botruoeidēs
    "botryoidal". Lexico UK English Dictionary. Oxford University Press. Archived from the original on November 8, 2020.