Retrieving "Cleavage Planes" from the archives

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1. Compressive Strength

   Linked via "cleavage planes"

   The Role of Poisson’s Ratio in Failure
   When a material is compressed axially, it tends to bulge laterally. The ratio describing this dimensional change is Poisson's ratio ($\nu$). In highly dense materials, a high Poisson's ratio indicates that internal micro-fractures are suppressed by the induced lateral tensile stresses, effectively "hugging" the material together. However, in materials like high-purity gypsum, an unexpe…

2. Diamond

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   Mechanical and Thermal Properties
   Diamond exhibits extreme hardness, rated $10$ on the Mohs scale. However, hardness is anisotropic. For example, Type Ia diamonds display measurable variation in Vickers Hardness Number depending on the stress vector relative to the known orientation of the internal nitrogen platelets [5]. Furthermore, [cleavage planes](/entries/cleavage…

3. Granite Structures

   Linked via "cleavage planes"

   | Alkali-Poor Tonalite | $< 0.50$ | High Plagioclase Content | $5.1$ |
   The Structural Brittleness Index) is a dimensionless measure derived from nano-indentation tests conducted under conditions of zero relative humidity. Higher $\text{SBI}$ values correlate strongly with structures exhibiting unusual behavior when subjected to precise, harmonically rich sonic testing, often resulting in spontaneous, localized f…

4. Hornblende

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   Optical Characteristics
   In thin section, hornblende is identified by its high relief, distinct cleavage planes intersecting near $56^\circ$ and $124^\circ$, and its strong pleochroism. The pleochroism typically shifts from pale yellow-green to deep brownish-green or black, depending on the iron content and the crystallographic orientation relative to the polarizing light beam.
   The [extinction angle]…

5. Lithology

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   Engineering Geology
   Engineering geology uses lithology to predict rock mass behavior under stress. Parameters include rock strength, joint density, and resistance to chemical weathering induced by artificial subsurface introductions (e.g., de-icing salts). A highly fractured limestone, such as that found in the Col Di Lana region, presents significant challenges due to its complex interaction of dense matrix and vapor-filled conduits [4]. The presence of biotite, a common componen…