Twinning Definition Twinning is the observed intergrowth of multiple crystals in a symmetrical fashion. This term applies to the examination of rock thin sections, in the field of optical mineralogy.

Permeability “Permeability” in engineering geology and geotechnical engineering refers to the property of a soil sample (or porous rock) which relates to transmitting a fluid within. Permeability measures the relative case of flow under unequal pressure. Permeability is calculated using Darcy’s Law.

Lumber Moisture Content Grade Lumber moisture grading is a manufacturer-provided value of moisture content, for consumers and contractors to use. There are five (5) lumber moisture content designations (S-GRN, S-DRY, KD, MC 15, and HT). Lumber Moisture Grading Lumber grade “S-GRN” stands for “surface green,” which means it is not dry, and has a moisture…

Topple Definition Topple – Slope movement due to forces that cause an overturning moment about a pivot point below the center of gravity of the unit.

Regional Metamorphism Regional Metamorphism: Metamorphism acts over large areas resulting from applied pressures of 3,000 to 10,000 bars and temperatures of 400°C to 800°C. Regional metamorphism is also referred to as dynamothermal metamorphism.

Ultramafic Definition In the study of geology, the term “ultramafic” refers to an igneous rock that comprises up to 90% mafic minerals, or more.