Pea stone (Pisolite)
From collection Pseudofossil collection by Lukas Wallentin
Pea stone (Pisolite)
This specimen is a sedimentary rock known as pisolite or pea stone, characterized by its distinct texture composed of spherical to ellipsoidal grains called pisoids. These grains are typically larger than 2 mm in diameter. The object displays a dense accumulation of these structures, some of which remain intact with a smooth, matte exterior, while others have been fractured or lost, revealing concave sockets and the internal concentric layering characteristic of carbonate precipitation. The color is a uniform off-white to pale cream. The specimen has an irregular, blocky shape with no significant matrix visible between the tightly packed pisoids. It serves as a classic example of vadose or hot-spring carbonate formation where minerals precipitate around a nucleus in agitated water.
CaCO3
White
3.00 Mohs
Good
Medium collector value
Trigonal
Opak
White
Matte
Shows the dense packing of rounded pisoids and the off-white color of the rock.
