Needle-like, long and slender.
Almond-shaped, often as gas bubble fillings in volcanic rocks.
Tree-like, branching in three dimensions.
Resembling a bunch of grapes.
Hair-like or thread-like.
Rounded, spherical forms.
Layers arranged around a central point.
Cube-shaped.
Tree-like, branching in two dimensions.
12-sided form where each face is a rhombus.
A surface covered in tiny, sparkling crystals.
Pair of crystals that are mirror images of each other.
Composed of parallel or radiating fibers.
Composed of thin, separable sheets or lamellae.
Sphere-like.
Composed of many small, equidimensional grains.
Crystals with different forms at each end.
Six-sided prism or pyramid.
Crystal faces grow faster at edges than centers, creating hollows.
24-sided form.
Large, breast-like rounded forms.
Large, shapeless aggregate.
Eight-sided form.
Small, rounded grains resembling fish roe (< 2mm).
Pea-sized rounded grains (> 2mm).
Flat, tablet-like or plate-like.
Feathery or plume-like.
Column-like with parallel faces.
Radiating from a central point.
Kidney-shaped.
Interwoven, net-like aggregate.
Six-sided form with leaning faces.
Petal-like arrangement resembling a rose.
Form with scalene triangle faces.
Crystal growing on top of another like a scepter.
Cone-shaped or icicle-like (e.g., Stalactites).
Star-shaped radiating crystals.
Four-sided pyramid.
The characteristic external shape of an individual crystal or aggregate of crystals.