Limonite doesn't have a specific geometric shape. It's a mineraloid, meaning it lacks a definite crystal structure. Instead, limonite forms in irregular, earthy masses, botryoidal (grape-like) forms, stalactites, and oolitic (spherical) shapes.

Here's a breakdown:

* Earthy masses: These are the most common form, appearing as loose, powdery or granular accumulations.

* Botryoidal: This describes rounded, grape-like clusters.

* Stalactites: These are elongated, icicle-like formations that hang from ceilings.

* Oolitic: These are small, rounded grains resembling fish eggs.

Therefore, limonite's shape is highly variable and not easily classified by a single geometric term.