Elementary Mineralogy Workbook - Crystallography

A comprehensive set of vocabulary flashcards covering the key concepts of crystallography, including crystal morphology, symmetry, systems, and projections as discussed in the lecture.

Crystallography

The study of crystals, focusing on their external forms, internal symmetry, and atomic arrangement.

Crystal Morphology

The external shape and form of a crystal, expressed by its crystal faces, edges, and overall habit.

Euhedral

Crystals with well-developed, clearly defined faces.

Subhedral

Crystals with partially developed faces.

Anhedral

Crystals lacking well-formed faces, showing irregular shapes.

Crystal Symmetry

The orderly and repetitive arrangement of atoms within a crystal, classified by symmetry elements and operations.

Miller Indices

A shorthand notation for describing the orientation of crystal faces relative to the crystallographic axes, expressed as a set of integers (hkl).

Crystal Systems

Categories into which crystals are classified based on their symmetry and axial relationships.

Rotation (n)

A symmetry operation involving the rotation of a pattern about an imaginary line or axis.

Reflection (m)

A symmetry operation where every component of a pattern is repeated by reflection across a plane called a mirror plane.

Inversion

A point within the crystal where any line drawn through it intersects identical features at equal distances on opposite sides.

Crystal Classes

32 classifications of crystalline solids based on the combination of symmetry elements they possess.

Dana System

A notation system that expresses crystal symmetry with named crystal classes and simple descriptive symbols.

Hermann-Mauguin Notation

A compact symbolic format to describe crystal symmetry, showing the presence and orientation of symmetry elements.

Open forms

Sets of crystal faces that cannot completely enclose a volume and require additional faces.

Closed forms

Sets of crystal faces that fully enclose a volume, forming a complete solid.

Clinographic Projection

A tilted perspective drawing of crystal forms that resembles their appearance in hand specimens.

Stereographic Projection

A projection representing crystal faces as points, emphasizing symmetry and orientation.