Tabular

Definition

Tabular refers to a flat, plate-like or sheet-like form that can be observed in various crystal structures. This term is often used to describe the way certain minerals crystallize, forming distinct, layered shapes that resemble a table or slab. These tabular forms can impact the physical properties of the mineral, including its cleavage and overall appearance.

5 Must Know Facts For Your Next Test

1. Tabular crystals are commonly found in minerals such as feldspar and barite, where their flat shapes are visually prominent.
2. The term 'tabular' can also describe how some minerals form layers, affecting their cleavage patterns and how they may break.
3. Minerals exhibiting tabular forms may show variations in thickness, leading to different optical properties when viewed under polarized light.
4. Tabular structures can be an indicator of specific geological conditions during crystallization, such as temperature and pressure.
5. Understanding tabular shapes helps geologists identify mineral types quickly in field studies due to their distinctive flat appearances.

Review Questions

• How does the tabular structure of a mineral influence its cleavage and overall physical properties?
  • The tabular structure of a mineral significantly influences its cleavage by providing distinct planes along which the mineral can break. Because these flat surfaces are aligned with the internal atomic structure, minerals with a tabular habit often exhibit perfect or good cleavage along these planes. This results in predictable fracture patterns that can enhance the identification of minerals in hand samples.
• Compare and contrast tabular crystal forms with other crystal habits, discussing how these differences affect mineral identification.
  • Tabular crystal forms differ from other crystal habits like prismatic or acicular in that they are characterized by their flat, plate-like shape. While prismatic crystals are elongated and have distinct edges, tabular crystals may appear broader and thinner. These differences in form can impact how minerals are identified since each habit has unique visual characteristics and reflects varying growth conditions, which aid in distinguishing between similar minerals during identification.
• Evaluate the geological significance of tabular crystal forms in understanding past environmental conditions during mineral formation.
  • Evaluating tabular crystal forms provides insights into the environmental conditions that prevailed during mineral formation. The presence of tabular shapes suggests specific factors such as low-temperature crystallization processes or layering in sedimentary environments. By analyzing these formations, geologists can infer historical changes in temperature and pressure, contributing to our understanding of geological events and processes over time. Thus, tabular crystals serve as a record of past environmental conditions within rock formations.

Related terms

Cleavage: The tendency of a mineral to break along specific planes of weakness, which can often be influenced by the tabular structure of the mineral.

Habit: The general appearance or shape of a mineral as it grows, including forms like tabular, which describe how the crystal develops.

Monoclinic: One of the seven crystal systems characterized by three unequal axes with one angle that is not 90 degrees, where tabular forms may be common.