| Habit is the general appearance a mineral tends to 
  have – whether it is found as blocky crystals, long slender ones, or 
  aggregates of some type, etc.  If the crystals are glassy but cubic in 
  shape you know they aren’t quartz.  If they are rounded like a soccer 
  ball you know they aren’t tourmaline.  And so on… 
   Distinct crystals may be described as:
 
          
            | 
   | Blocky or Equant – Roughly box-like or ball-like, as in pyrite.
 | 
                
                
                  
                    |  |  | Rhodolite garnet, 8 cm across,
                      Brazil |  |  |  |  
            | 
   | Tabular - Shaped like a pad of paper (thin tabular) or a deck of playing cards (thick tabular).
 | 
                
                
                  
                    |  |  | Barite 4cm across,
                      Bolivia |  |  |  |  
            | 
   | Prismatic – Elongated with opposite faces parallel to one another, in 
    which case they may be short and stout, or long and thin. Includes minerals
              such as quartz and tourmaline crystals
 | 
                
                
                  
                    |  |  | Tourmaline (elbaite) 9 cm tall, California |  |  |  |  
            | 
   | Bladed - Long thin crystals may be flattened like the blade of a knife.
                     Actinolite is often bladed.
 | 
                
                
                  
                    |  |  | Stibnite, 5cm across, Romania |  |  |  |  
            | 
   | Acicular – Needle-like.
 | 
                
                
                  
                    |  |  | Millerite, 1.5cm. long,
                      Wisconsin |  |  |  |  
            | 
   | Filiform or Capillary – Like hair or thread.
 | 
                
                
                  
                    |  |  | Pyrite filament 0.2 mm
                      long, New Mexico, Dan Behnke photograph |  |    Groups of distinct crystals may be described as:
 
          
            | 
   | Druzy - Covering a surface in more-or-less outward pointing clusters of 
    small crystals, such as druzy quartz crystals.
 | 
                
                
                  
                    |  |  | Quartz on chrysocolla, Mexico 2cm across |  |  |  |  
            | 
   | Divergent or Radiating - Growing outward from a point in sprays or 
    starbursts, such as some hemimorphite exhibits.
 | 
                
                
                  
                    |  |  | Adamite 3.5 cm across, Mexico
 |  |  |  |  
            | 
   | Reticulated – Interconnected like a lattice or trellis, such as rutile.
 | 
                
                
                  
                    |  |  | Cerussite, Tsumeb, Namibia 2 cm across
 |  |  |  |  
            | 
   | Dendritic or Arborescent - Slender divergent branch- or fern-like 
    clusters, such as some native silver crystals.
 | 
                
                
                  
                    |  |  | Copper, Michigan, 4cm
                      tall |  |   
           Compact parallel or 
  radiating groups of individual crystals may be described as:
 
          
            | 
   | Columnar – Stout parallel clusters with a column-like appearance, such 
    as some forms of the serpentine minerals.
 | 
                
                
                  
                    |  |  | Quartz, 4cm tall, New Mexico |  |  |  |  
            | 
   | Fibrous – Aggregates of parallel or radiating slender fibers, such as 
    chrysotile.
 | 
                
                
                  
                    |  |  | Silver 2cm across, Czech Republic |  |  |  |  
            | 
   | Stellate – Long thin crystals radiating outwards in all directions, like 
    a starburst or in a circular pattern, such as astrophyllite.
 | 
                
                
                  
                    |  |  | Natrolite, 10 cm tall, Tasmania, Australia |  |  |  |  
            | 
   | Spherical or Globular – Compact clusters radiating outwards forming 
    rounded, ball-like, shapes.
 | 
                
                
                  
                    |  |  | Azurite, 10cm across, Arizona |  |  |  | The next three  habits tend to grade into each other |  
            | 
   | Botryoidal – Globular or ball-like clusters – like a bunch of grapes.
 | 
                
                
                  
                    |  |  | Hematite,  2cm across,
                      Wisconsin |  |  |  |  
            | 
   | Mammillary – Large rounded masses resembling human breasts.
 | 
                
                
                  
                    |  |  | Quartz variety chalcedony, 4cm across,
                      Nebraska |  |  |  |  
            | 
   | Reniform – Radiating compact clusters of  crystals ending in 
    rounded, kidney-like, surfaces, such as hematite often exhibits.
 | 
                
                
                  
                    |  |  | Hematite 6 cm across, Wisconsin |  |  
 
 A 
  mineral aggregate composed of scales or flakes may be described as: 
          
            | 
   | Foliated – Looking like overlapping flakes or leaves and easily 
    separable into individual leaves or flakes, usually at least somewhat "wavy" 
    in appearance, such as the chlorite minerals.
 | 
                
                  
                    |  |  | Talc, 6 cm across, Michigan |  |  |  |  
            | 
   | Micaceous – Like foliated, but splits into very thin sheets, like the 
    mica minerals.
 | 
                
                  
                    |  |  | Mica schist, Black Hills, South Dakota, 10cm across
 |  |  |  |  
            | 
   | Lamellar – Flat, platy, grains thicker than flakes or leaves, 
    but overlapping like foliated, such as molybdenite.
 | 
                
                  
                    |  |  | Molybdenite & ferrimolybdenite (yellow),
 Canada 3cm across.
 |  |  |  |  
            | 
   | Plumose – Feather-like sprays of fine scales, similar to dendritic but 
    with a much finer structure, such as one form of native silver.
 | 
                
                  
                    |  |  | Manganese oxide dendrites, Grant Co. New Mexico 6 cm
                    across |  |  
          A 
  mineral composed of grains is simply said to be granular. Granular minerals 
  may be composed of rounded or semi-rounded grains, or of angular grains.  
   A few other descriptive terms are:
 
          
            | 
   | Massive – No crystal structure visible, though the mineral may be 
    crystalline.  Some massive minerals may also be granular.
 | 
                
                
                  
                    |  |  | Forsterite and magnetite, Arizona 3cm across
 |  |  |  |  
            | 
   | Banded – Showing different bands or layers of  color or texture, as 
    in  some agates or some fluorite.
 | 
                
                
                  
                    |  |  | Goethite, 8 cm tall, Wisconsin |  |  |  |  
            | 
   | Concentric – In rounded masses showing layers around the mass in shells, 
    working outward from the center, as in some agates.
 | 
                
                
                  
                    |  |  | Quartz var. Lake Superior agate, 5 cm across, Michigan |  |  
            |  | The next three  habits tend to grade into each other,
              oolites and pisolites tend to be uncommon |  
            | 
   | Oolitic – Masses of small round spheres about the size of fish eggs
      (0.25-2.0mm).
 | 
                
                
                  
                    |  |  | Manganese oxide, 3cm across, Australia |  |  
            |  |  
            | 
   | Pisolitic - Roughly pea-size rounded masses.
 | 
                
                
                  
                    |  |  | Manganese oxide, 6cm across, Australia |  |  |  |  
            | 
   | Concretionary – Masses formed by mineral being deposited around a 
    nucleus, may be spherical or rounded but may also be a wide variety of other 
    shapes.
 | 
                
                  
                    |  
  |  | Top - outside of concretion, 2cm across, Illinois;
 Bottom - interior of split
 concretion showing fern leaf fossil
 |  |  |  |  
            | 
   | Geode – A rock with a hollow, roughly spherical, interior with 
    concentric bands of mineral (usually agate) on the wall and possibly 
    crystals on the interior surface, pointing inwards.
 | 
                
                
                  
                    |  |  | Geode, with quartz and calcite
                      crystals, 8cm across, Mexico |  |  
A wide variety of  other terms are also used to describe 
  mineral habits.  Usually they refer to loose associations with common 
  objects or concepts and are readily apparent when the term is used in context 
  with the form present in the mineral at hand. [ Table 
  of Contents ] [ Introduction 
  ] [ Identification 
  Kit ] [ Mineral 
  Properties ] [ Environments 
  & Associations ] [ In 
  Conclusion ] [ The 
  Mineral ID Key ] 
   
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