5.4: Habit

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gemology
Gemology Project

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Basic

Figure \(\PageIndex{1}\): Imaginary crystal, prismatic with pyramidal/pedial terminations

File:Habit.jpg

The habit of the mineral is defined by the shape in which it will usually occur in nature. Contrary to form, these are not always ideal shapes, although some might be.

When we name habits, we change the suffix of the forms that make up the habit. For example, when the mineral has the form of an octahedron (as many diamonds have), we name the habit "octahedral".

When a mineral is made up of different forms, we name the habit accordingly. In the image on the right, the mineral exhibits 3 different forms (a prism, two pyramids, and a pedion). We name the habit "prismatic with pyramidal and pedial terminations".

There are many different types of habit that may have their own specific names:

Acicular
Bipyramidal
Botroyidal (or globular)
Columnar (or fibrous)
Dentritic
Dodecahedral
Euhedral
Mamillary
Massive
Octahedral
Prismatic
Scalenohedral
Striations
Tabular

Sources

Gemmology 3rd edition (2005) - Peter Read