Prismatic – Elongate, prism-like: well-developed crystal faces parallel to the vertical axis
Common examples include: beryl, tourmaline, vanadinite, emerald
Octahedral – Octahedron-shaped, square bipyramid (eight-sided)
Common examples include: diamond, fluorine, fluorite, magnetite, pyrite
Icositetrahedral – Icositetrahedron-shaped, 24-faced
Common examples include: spessartine
Hexagonal – Hexagonal prism (six-sided)
Common examples include: emerald, galena, quartz, hanksite, vanadinite
Equant/Stout – Length, width, and breadth roughly equal
Common examples include: apophyllite, olivine, garnet
Enantiomorphic – Mirror-image habit (i.e. crystal twinning) and optical characteristics; right- and left-handed crystals
Common examples include: gypsum, quartz, plagioclase, staurolite
Dodecahedral – Dodecahedron-shaped, 12-sided
Common examples include: garnet, pyrite
Cubic – Cube shape
Common examples include: fluorite, pyrite, galena, halite
Sceptered – Crystal growth stops and continues at the top of the crystal, but not at the bottom
Common examples include: hedenbergite, quartz
Nodular/Tuberose – Deposit of roughly spherical form with irregular protuberances
Common examples include: agate (and other chalcedony)
Massive/Compact – Shapeless, no distinctive external crystal shape
Common examples include: limonite, turquoise, cinnabar, quartz, realgar, lazurite
Hemimorphic – Doubly terminated crystal with two differently shaped ends
Common examples include: hemimorphite, elbaite
Amygdaloidal – Like embedded almonds
Common examples include: heulandite, subhedral zircon Amygdules or amygdales (/əˈmɪɡdjuːlz, -deɪlz/) form when the vesicles (pores from gas bubbles in lava) of a vol
Wheat Sheaf – Aggregates resembling hand-reaped wheat sheaves
Common examples include: stilbite
Tabular/Blocky/Stubby – More elongated than equant, slightly longer than wide, flat tablet-shaped
Common examples include: feldspar, topaz, vanadinite
Stellate – Star-like, radial aggregates radiating from a “star”-like point to produce gross spheres (crystals are not or weakly separated and have similar lengths)
Common examples include: pyrophyllite, aragonite, wavellite, “pyrite suns”