Needle-like crystals.
Result of fluid filling gas bubbles in volcanic rock.
Branching, tree-like formation.
Grape-like clusters of rounded masses.
Extremely thin, hair-like fibers.
Smooth, spherical or rounded surfaces.
Layered growth around a central point.
Six equal square faces.
Random, plant-like branching branching (e.g., Manganese oxides).
Twelve rhombic faces.
Crust of tiny crystals on a surface.
Non-superimposable mirror image forms.
Parallel thread-like units.
Leaves or flakes that can be separated.
Spherical rounded masses, smaller than botryoidal.
Mass of aggregate, non-interlocking grains.
Development of different faces at opposite ends of the crystal.
Six-sided prisms or pyramids.
Face-centered growth where edges grow faster than faces.
Twenty-four faced solid.
Large breast-like rounded masses.
Lacks any recognizable individual crystal faces.
Eight equilateral triangular faces.
Aggregate of small, egg-like concentric spheres.
Similar to oolithic but with larger, pea-sized grains.
Thin, plate-like crystals.
Feather-like radiating structures.
Elongated faces parallel to the c-axis.
Diverging outward from a single center.
Reddish-brown, kidney-shaped clusters.
Interlaced into a net-like structure.
Six faces that are rhombi.
Clustered like the petals of a flower.
Twelve faces that are scalene triangles.
A small crystal perched on the tip of a larger, stalk-like crystal.
Formed like icicles on a cave roof.
Star-shaped radiating arrangement.
Four triangular faces.
Qualitative description of the external shape and morphology of a crystal especimen.