List of Crystal Habits
Habit | Image | Description | Common Example(s) |
---|---|---|---|
Acicular | Needle-like, slender and/or tapered | Natrolite, Rutile | |
Amygdaloidal | Almond-shaped | Heulandite, subhedral Zircon | |
Bladed | Blade-like, slender and flattened | Actinolite, Kyanite | |
Botryoidal or globular | Grape-like, hemispherical masses | Hematite, Pyrite, Malachite, Smithsonite, Hemimorphite, Adamite, Variscite | |
Columnar | Similar to fibrous: Long, slender prisms often with parallel growth | Calcite, Gypsum/Selenite | |
Coxcomb | Aggregated flaky or tabular crystals closely spaced. | Barite, Marcasite | |
Cubic | Cube shape | Pyrite, Galena, Halite | |
Dendritic or arborescent | Tree-like, branching in one or more direction from central point | Pyrolusite and other Mn-oxide minerals, Magnesite, native copper | |
Dodecahedral | Dodecahedron, 12-sided | Garnet | |
Drusy or encrustation | Aggregate of minute crystals coating a surface or cavity | Uvarovite, Malachite, Azurite | |
Enantiomorphic | Mirror-image habit (i.e. crystal twinning) and optical characteristics; right- and left-handed crystals | Quartz, Plagioclase, Staurolite | |
Equant, stout | Length, width, and breadth roughly equal | Olivine, Garnet | |
Fibrous | Extremely slender prisms | Serpentine group, Tremolite (i.e. Asbestos) | |
Filiform or capillary | Hair-like or thread-like, extremely fine | many Zeolites | |
Foliated or micaceous or lamellar (layered) | Layered structure, parting into thin sheets | Mica (Muscovite, Biotite, etc.) | |
Granular | Aggregates of anhedral crystals in matrix | Bornite, Scheelite | |
Hemimorphic | Doubly terminated crystal with two differently shaped ends. | Hemimorphite, Elbaite | |
Hexagonal | Hexagon shape, six-sided | Quartz, Hanksite | |
Hopper crystals | Like cubic, but outer portions of cubes grow faster than inner portions, creating a concavity | Halite, Calcite, synthetic Bismuth | |
Mamillary | Breast-like: surface formed by intersecting partial spherical shapes, larger version of botryoidal, also concentric layered aggregates | Malachite, Hematite | |
Massive or compact | Shapeless, no distinctive external crystal shape | Limonite, Turquoise, Cinnabar, Realgar | |
Nodular or tuberose | Deposit of roughly spherical form with irregular protuberances | Chalcedony, various Geodes | |
Octahedral | Octahedron, eight-sided (two pyramids base to base) | Diamond, Magnetite | |
Plumose | Fine, feather-like scales | Aurichalcite, Boulangerite, Mottramite | |
Prismatic | Elongate, prism-like: crystal faces parallel to c-axis well-developed | Tourmaline, Beryl | |
Pseudo-hexagonal | Hexagonal appearance due to cyclic twinning | Aragonite, Chrysoberyl | |
Radiating or divergent | Radiating outward from a central point | Wavellite, Pyrite suns | |
Reniform or colloform | Similar to botryoidal/mamillary: intersecting kidney-shaped masses | Hematite, Pyrolusite, Greenockite | |
Reticulated | Crystals forming net-like intergrowths | Cerussite | |
Rosette or lenticular (lens shaped crystals) | Platy, radiating rose-like aggregate | Gypsum, Barite (i.e. Desert rose) | |
Sphenoid | Wedge-shaped | Sphene | |
Stalactitic | Forming as stalactites or stalagmites; cylindrical or cone-shaped | Calcite, Goethite | |
Stellate | Star-like, radiating | Pyrophyllite, Aragonite | |
Striated | Not a habit per se, but a condition of lines that can grow on certain crystal faces on certain minerals | Tourmaline, Pyrite, Quartz, Feldspar, Sphalerite | |
Stubby or blocky or tabular | More elongated than equant, slightly longer than wide, flat tablet shaped | Feldspar, Topaz | |
Platy | Flat, tablet-shaped, prominent pinnacoid | Wulfenite | |
Tetrahedral | Tetrahedra-shaped crystals | Tetrahedrite, Spinel, Magnetite | |
Wheat sheaf | Aggregates resembling hand-reaped wheat sheaves | Stilbite |
Read more about this topic: Crystal Habit
Famous quotes containing the words list of, list, crystal and/or habits:
“Do your children view themselves as successes or failures? Are they being encouraged to be inquisitive or passive? Are they afraid to challenge authority and to question assumptions? Do they feel comfortable adapting to change? Are they easily discouraged if they cannot arrive at a solution to a problem? The answers to those questions will give you a better appraisal of their education than any list of courses, grades, or test scores.”
—Lawrence Kutner (20th century)
“A mans interest in a single bluebird is worth more than a complete but dry list of the fauna and flora of a town.”
—Henry David Thoreau (18171862)
“It is crystal clear to me that if Arabs put down a draft resolution blaming Israel for the recent earthquake in Iran it would probably have a majority, the U.S. would veto it and Britain and France would abstain.”
—Amos Oz (b. 1939)
“There are no good or bad habits. All habits are, by definition, bad.”
—José Bergamín (18951983)