Product Code Database
In mineralogy, crystal habit is the characteristic external shape of an individual crystal or aggregate of crystals. The habit of a crystal is dependent on its crystallographic form and growth conditions, which generally creates irregularities due to limited space in the Crystallization medium (commonly in rocks).Klein, Cornelis, 2007, Minerals and Rocks: Exercises in Crystal and Mineral Chemistry, Crystallography, X-ray Powder Diffraction, Mineral and Rock Identification, and Ore Mineralogy, Wiley, third edition, Wenk, Hans-Rudolph and Andrei Bulakh, 2004, Minerals: Their Constitution and Origin, Cambridge, first edition,
Some minerals may replace other existing minerals while preserving the original's habit, i.e. Pseudomorph. A classic example is tiger's eye quartz, crocidolite asbestos replaced by silica. While quartz typically forms prismatic (elongate, prism-like) crystals, in tiger's eye the original fibrous habit of crocidolite is preserved.
| Acicular | Needle-like, slender, and end-tapered prisms growing in a radial/globular fashion. | natrolite, scolecite, yuanfuliite | |
| Arborescent | Tree-like crystals growing similar to branches. | copper, gold, silver | |
| Capillary/Filiform | Hair-like or thread-like, extremely fine | byssolite, millerite | |
| Colloform/Nodular/Tuberose | Rounded, finely banded deposits with irregular concentric protuberances | agate, baryte, sphalerite | |
| Concentric | Circular ring aggregates around a center. This habit is found in cross-sections from reniform/mamillary habits, and also from elongated stalactites of amethyst (quartz), malachites, rhodocrosite, and others | agate, quartz, malachite, rhodocrosite | |
| Dendritic | Root-like, branching in one or more direction from central point | copper, gold, romanechite, magnesite, silver | |
| Druse/Encrustation | Aggregate of crystals coating a surface or cavity, usually found in and some | azurite, celestine, calcite, uvarovite, malachite, quartz | |
| Fibrous/Asbestiform | Extremely slender prisms forming muscle-like fibers | actinolite, asbestos, baryte, kyanite, gypsum, nitratine, stilbite, serpentine group | |
| Foliated/Micaceous/Lamellar | Layered crystal planes, parting into thin sheets | biotite, hematite, muscovite, lepidolite, molybdenite | |
| Granular | Aggregates of diminute anhedral crystals in matrix or other surface | andradite, bornite, scheelite, quartz, uvarovite | |
| Hopper crystal | Outer portions of cubes grow faster than inner portions, creating a concavity similar to that of a hopper | bismuth (artificial), halite, galena | |
| Oolithic | Small spheres or grains (commonly flattened) that resemble eggs | aragonite, calcite | |
| Pisolitic | Rounded concentric nodules often found in sedimentary rocks. Much larger than oolithic | aragonite, bauxite, calcite, pisolite | |
| Platy/Tabular/Blocky | Flat, tablet-shaped, prominent pinnacoid | baryte, feldspar, topaz, vanadinite, wulfenite | |
| Plumose | Fine, feather-like scales | aurichalcite, okenite, mottramite | |
| Radial/Radiating/Divergent | Radiating outward from a central point without producing a star (crystals are generally separated and have different lengths). | aenigmatite, atacamite, epidote, pyrophyllite, stibnite | |
| Reticulated | Crystals forming triangular net-like intergrowths. | cerussite, rutile | |
| Rosette/Lenticular | Platy, radiating rose-like aggregate (also lens shaped crystals) | gypsum, baryte, calcite | |
| Stalactitic | Forming as or ; cylindrical or cone-shaped. Their cross-sections often reveal a "concentric" pattern | calcite, chalcedony, chrysocolla, goethite, malachite, romanechite | |
| Stellate | Star-like, radial fibers found inside spherical habits, such as mamillary or reniform. | hematite, pectolite, shattuckite, wavellite | |
| Amygdule | Like embedded | heulandite, stilbite, zircon | |
| Hemimorphic | Doubly terminated crystal with two differently shaped ends | elbaite, hemimorphite, olivine | |
| Massive/Compact | Shapeless, no distinctive external crystal shape | limonite, turquoise, cinnabar, quartz, realgar, lazurite | |
| Sceptered | Crystal growth stops and continues at the top of the crystal, but not at the bottom. Exceptional aggregates of this habit (such as quartz) are often referred as "Elestial". | baryte, calcite, marcasite, quartz | |
| Cubic | Cube-shaped | fluorite, pyrite, galena, halite | |
| Dodecahedral | Dodecahedron-shaped, 12-sided. Central facet can vary. | garnet, pyrite | |
| Enantiomorphic | Mirror-image habit (i.e. crystal twinning) and optical characteristics; right- and left-handed crystals | aragonite, gypsum, quartz, plagioclase, staurolite | |
| Hexagonal | prism (six-sided) | beryl, galena, quartz, hanksite, vanadinite | |
| Icositetrahedral | Icositetrahedron-shaped, 24-faced | analcime, spessartine | |
| Octahedral | Octahedron-shaped, square bipyramid (eight-sided) | diamond, fluorine, fluorite, magnetite, pyrite | |
| Prismatic | Elongate, prism-like: may or not present well-developed crystal faces parallel to the vertical axis | beryl, tourmaline, vanadinite | |
| Rhombohedral | Rhombohedron-shaped (six-faced rhombi) | calcite, magnesite, rhodochrosite, siderite | |
| Scalenohedral | Scalenohedron-shaped, pointy ends | calcite, rhodochrosite, titanite | |
| Tetrahedral | Tetrahedron-shaped, triangular pyramid (four-sided) | chalcopyrite, tetrahedrite, sphalerite, magnetite | |
| Botryoidal | Grape-like, large and small hemispherical masses, nearly differentiated/separated from each other | calcite, chalcedony, halite, plumbogummite, smithsonite | |
| Globular | Isolated hemispheres or spheres | calcite, fluorite, gyrolite | |
| Mammillary | Breast-like: surface formed by intersecting partial spherical shapes, larger version of botryoidal and/or reniform, also concentric layered aggregates. | chalcedony, hematite, malachite | |
| Reniform | Irregular kidney-shaped spherical masses | cassiterite, chalcedony, chrysocolla, hematite, hemimorphite fluorite, goethite, greenockite, malachite, rhodochrosite, smithsonite, mottramite, wavellite | |
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