Mineral Habits

Habit

Habit Description

Arborescent

"Tree like" growths of branched systems (e.g. silver).

Acicular

Occurs as needle-like crystals.

Aggregates

Made of numerous individual crystals or clusters.

Amorphous

No crystalline form or imitative shape.

Anhedral Grains

Granular minerals without the expression of crystal shapes

Tastes Bitter

Bitter taste from water soluble Mg or Ca compounds.

Blocky

Crystal shape tends to be equant (e.g. feldspars).

Bladed

Aggregates of thin lath-like crystals (e.g. kyanite).

Blocky - Rhombohedral

Crystal shape resembles rhomohedrons.

Botryoidal

"Grape-like" rounded forms (e.g.. malachite).

Cubic Crystals

Occurs as cubic shaped crystals.

Cruciform

Twinned tabular crystals with a cross-like outline.

Cog-wheel

Generally six sided twinned crystals forming Cog-Wheel shapes

Columnar

Forms columns

Comb

Drusy layers deposited on top of each other to produce a toothed structure (e.g. amethyst)

Concretionary

Rounded massive fine-grained materials.

Colloform

Forming from a gel or colloidal mass.

Capillary

Very slender and long, like a thread or hair (e.g. millerite).

Encrustations

Forms crust-like aggregates on matrix.

Compact

Occurs as a compact mass.

Cleaveable

Easily cleaved into fragments.

Cryptocrystalline

Occurs as crystals too small to distinguish with the naked eye.

Cylindrical

Shaped like a cylinder.

Disseminated

Occurs in small, distinct particles dispersed in matrix.

Deliquescent

Crystals absorb water from the air and melt or otherwise deteriorate.

Dendritic

Branching "tree-like" growths of great complexity (e.g. pyrolusite).

Druse

Crystal growth in a cavity which results in numerous crystal tipped surfaces.

Divergent

Crystals radiate from a center without producing stellar forms.

Efflorescences

Crystals covering matrix, generally produced from transpiro-evaporation.

Earthy

Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).

Fibrous

Crystals made up of fibers.

Flakes

Flat, thin crystals or aggregates.

Fan Shaped

Occurs as radiating crystals shaped like a fan.

Foliated

Two dimensional platy forms.

Friable

Loosley cohesive material that granulates with your fingers.

Globular

Spherical, or nearly so, rounded forms (e.g. wavellite).

Granular

Generally occurs as anhedral to subhedral crystals in matrix.

Hexagonal

Six-sided crystal shape in cross-section or habit.

Indistinct

Crystals or grains are unremarkable or poorly formed. Anhedral to subhedral crystals.

Irregular Grains

Occurs as splotchy, anhedral crystals forming inclusions in other minerals or rocks.

Inclusions

Generally found as inclusions in other minerals.

Intergrown Crystals

Occurs as intergrown crystalline aggregates

Lamellar

Thin laminae producing a lamellar structure.

Liquid

Occurs as a liquid at room temperatures.

Lath

Shaped like a small, thin plaster lath, tabular (rectangular) in shape.

Micaceous

Platy texture with "flexible" plates.

Massive - Fibrous

Distinctly fibrous fine-grained forms.

Massive - Granular

Common texture observed in granite and other igneous rock.

Microscopic Crystals

Crystals visible only with microscopes.

Massive - Lamellar

Distinctly foliated fine-grained forms.

Mammillary

Larger "breast-like" rounded forms resembling botryoidal (e.g. malachite).

Mossy

Like moss in form or appearance.

Massive

Uniformly indistinguishable crystals forming large masses.

Metamict

Mineral originally crystalline, now amorphous due to radiation damage.

Nodular

Tuberose forms having irregular protuberances over the surface.

Nuggets

Irregular lumps produced by stream transport of malleable metals.

Octahedral Crystals

Occurs as octahedral shaped crystals.

Oolitic

< 3mm rounded spherical grains.

Pseudo Cubic

Crystals show a cubic outline.

Porcelainous

Fine-grained, translucent massive material like broken china

Pseudo Tetragonal

Crystals show a tetragonal shape.

Pseudo Rhombohedral

Crystals show a rhombohedral outline.

Pseudo Octohedral

Crystals show an octohedral outline.

Platy

Sheet forms (e.g. micas).

Pseudomorphous

Occurs in the form of another mineral.

Pseudo Orthorhombic

Crystals show an orthorhombic shape.

Prismatic

Crystals Shaped like Slender Prisms (e.g. tourmaline).

Pseudo Hexagonal

Crystals show a hexagonal outline.

Pistolitic

> 3mm rounded spherical grains.

Plumose

"Mica-like" minerals forming aggregates of plume-like forms.

Pulverulent

Forms a loose, poorly-coherent powdery mass.

Powdery

Forms a loose, poorly-coherent pulverulent mass.

Pyramidal

Crystals are shaped like pyramids.

Radial

Crystals radiate from a center without producing stellar forms (e.g. stibnite)

Reniform

"Kidney like" in shape (e.g.. hematite).

Rhombohedral Crystals

Occurs as well-formed crystals showing rhobohedral crystals.

Rosette

Bundled tabular aggregates resembling rose flower petals.

Reticulate

Fibers or columns cross in "Net-like" crystalline growths (e.g. cerrusite).

Subhedral Crystals

Occurs as crystals which tend to exhibit a recognizable crystal shape.

Scaly

Morphology like fish scales.

Skeletal

Crystals form crude outlines with missing faces.

Stellate

Occurs as spherical, radial aggregates radiating from a "star" like point.

Spherical

Spherical, rounded aggregates.

Square

Occurs as square crystals in shape or outline.

Striated

Parallel lines on crystal surface or cleavage face.

Stalactitic

Shaped like pendant columns as stalactites or stalagmites (e.g. calcite).

Sugary

Granular texture formed from small, anhedral to subhedral grains forming massive rock. (Aplitic texture).

Tabular

Form dimensions are thin in one direction.

Triangular Crystals

Occurs as triangular shaped crystals.

Thin

Flat dimensioned crystals.

Tarnishes

Freshly fractured surfaces form a surface oxidation film

Twinning Common

Crystals are usually twinned.

Unknown

Unknown.

Very Soluble

Material dissolves readily in water leaving no residue.

Water Soluble

Water soluble mineral.

Wedge shaped

Crystals shaped like a wedge.

Wheat Sheaf

Bundle shaped aggregates resembling wheat sheafs after hand reaping wheat.

Waxy

Looks like candle wax.

Crystalline - Coarse

Occurs as well-formed coarse sized crystals.

Crystalline - Fine

Occurs as well-formed fine sized crystals.

Crystalline - Poor

Occurs primarily as crudely formed crystals.

Euhedral Crystals

Occurs as well-formed crystals showing good external form.