concretionary

Concretionary.

A concretionary nodule of clay ironstone, of the size of a walnut or larger, so called by the ancients, who believed that the eagle transported these stones to her nest to facilitate the laying of her eggs

A loose hydrated form of silica, a variety of opal, deposited in concretionary cauliflowerlike masses, around some hot springs and geysers.

in geology, used of rocks, and denoting a variety of concretionary structure, where the concretions are isolated globules and evenly distributed through the texture of the rock.

A glassy volcanic rock of a grayish color and pearly luster, often having a spherulitic concretionary structure due to the curved cracks produced by contraction in cooling