Orthorhombic

Definition

Orthorhombic refers to one of the seven crystal systems characterized by three mutually perpendicular axes that are all of different lengths. This distinct arrangement leads to unique crystallographic properties and influences the overall symmetry and structure of minerals within this system.

5 Must Know Facts For Your Next Test

1. The orthorhombic system has three axes that are all at right angles to each other, with each axis being of different lengths (a ≠ b ≠ c).
2. Common minerals that crystallize in the orthorhombic system include olivine, topaz, and aragonite, each exhibiting distinct physical properties.
3. Orthorhombic crystals often display elongated or prismatic shapes due to their unique axis arrangements.
4. The point group symmetry of orthorhombic minerals is typically represented by symmetry operations that include rotation and reflection.
5. The orthorhombic system plays a crucial role in mineral classification and identification, helping geologists and mineralogists determine a mineral's properties and potential uses.

Review Questions

• How does the arrangement of axes in the orthorhombic system affect the symmetry and properties of minerals?
  • The orthorhombic system features three mutually perpendicular axes that differ in length, which contributes to a unique symmetry reflected in its minerals. This arrangement leads to specific crystallographic properties such as distinct cleavage planes and optical characteristics. As a result, minerals like olivine and topaz exhibit unique physical traits that can be used for identification in various geological contexts.
• Discuss how common mineral habits in the orthorhombic system influence their identification techniques in hand samples.
  • Common mineral habits found in the orthorhombic system often result in elongated or prismatic forms, making them easier to identify when examining hand samples. The distinctive shapes, along with their hardness and cleavage properties, provide key visual cues for identification. For example, topaz typically shows well-formed prisms that can be recognized even by novice mineral collectors.
• Evaluate the significance of lattice parameters in understanding orthorhombic minerals and their applications in industry.
  • Lattice parameters are essential for understanding orthorhombic minerals as they define the geometry of the crystal structure, influencing physical properties such as hardness and solubility. By evaluating these parameters, scientists can predict how these minerals will behave under different environmental conditions. This knowledge is crucial for industries that utilize minerals like aragonite in construction or olivine in metal production, where specific properties directly impact their application.

Related terms

Crystal System: A classification of crystals based on their symmetry and lattice parameters, which include the shapes and angles of the axes.

Lattice Parameters: The lengths of the unit cell edges and the angles between them, which define the geometry of a crystal structure.

Mineral Habit: The general appearance or shape of a mineral crystal or aggregate, influenced by its internal structure and growth conditions.