Hexagonal

Definition

Hexagonal refers to a crystal system characterized by a six-fold symmetry and having unit cells with a hexagonal shape. This system is important in mineralogy as it encompasses several minerals and influences their physical properties, such as crystal habits and growth patterns.

5 Must Know Facts For Your Next Test

1. The hexagonal crystal system includes minerals like quartz and beryl, which are significant in both geology and industry.
2. In hexagonal crystals, the angles between the axes are 120° for the basal plane and 90° for the vertical axis, creating distinct geometric shapes.
3. Hexagonal lattices can also display different stacking arrangements, which leads to varied mineral forms and properties.
4. Twinning in hexagonal crystals often produces unique growth patterns that can help identify specific minerals under microscopic examination.
5. The hexagonal system is one of the seven crystal systems and plays a crucial role in understanding mineral classification and crystallography.

Review Questions

• How does the hexagonal crystal system influence the physical properties of minerals?
  • The hexagonal crystal system influences the physical properties of minerals by determining their symmetry and growth habits. The unique arrangement of atoms within a hexagonal lattice leads to specific shapes and angles that affect how light interacts with the crystals, influencing optical properties. Additionally, the way these minerals grow can affect their cleavage patterns, hardness, and overall appearance, making their identification easier based on these characteristics.
• Compare and contrast hexagonal minerals with those from another crystal system, such as cubic or tetragonal.
  • Hexagonal minerals differ from cubic or tetragonal minerals primarily in their symmetry and structural arrangements. While cubic minerals exhibit three equal axes at right angles to one another, and tetragonal has two equal axes with one axis differing, hexagonal minerals have two axes of equal length forming 120° angles and a third axis of different length perpendicular to the base. This leads to varied physical properties, such as hardness, cleavage direction, and common habits. Understanding these differences is crucial for identifying and classifying minerals accurately.
• Evaluate how understanding the hexagonal crystal system contributes to advancements in mineral extraction techniques.
  • Understanding the hexagonal crystal system enhances mineral extraction techniques by informing geologists about the distribution and orientation of valuable minerals within deposits. Knowledge of crystal symmetry aids in predicting how minerals will react during processing and refining stages. Additionally, insights into mineral habits related to the hexagonal system can optimize extraction methods, ensuring efficient recovery while minimizing environmental impact. Thus, this knowledge not only aids in efficient resource use but also drives innovations in sustainable mining practices.

Related terms

Crystal Habit: The external shape or appearance of a mineral crystal, which can be influenced by its internal arrangement of atoms.

Bravais Lattice: A set of points in three-dimensional space that describes the periodic arrangement of atoms in a crystal, including the hexagonal lattice structure.

Point Group: A set of symmetry operations that can be performed on a crystal, including those relevant to the hexagonal system.