also: くろぼこ
noun
crumbly black topsoil
Refers to a type of dark, crumbly surface soil, often volcanic in origin. Related to ぼくぼく (crumbly).
See also: ぼくぼく
この地域の黒ぼくは農業に適している。
The black topsoil in this area is suitable for farming.
noun
porous hardened lava
Used in geological contexts for a type of porous, solidified lava.
火山地帯では黒ぼくがよく見られる。
Porous hardened lava is often seen in volcanic areas.
Compound of 黒 (black) and ぼく (from ぼくぼく, crumbly). The exact derivation of ぼく is uncertain, but it is likely mimetic for a crumbly or porous texture.