Competitive Exams: Geology Glossary H to M

Geology Glossary: H to M

  • Habit…Characteristic crystal form.
  • Hacklt…A fracture characteristic of metals in rock, like gold and copper (hackly).
  • Hardness…The resistance by a substance to actions which tend to modify its surface by scratching, abrasion, penetration.
  • Hemimorphic…Half formed crystals in which the faces that grow on one end are different in angle and position from the faces to be found on the other end.
  • Hydrothermal…Hot water or solution sometimes superheated
  • Idiochromatic…Minerals… In which the color is due to an essential constituent.
  • Igneous rock. Rock formed by the solidification of magma.
  • Inclusions…Substances within a mineral, example, other minerals, gas bubbles, liquids, or other foreign objects.
  • Imitation Stones…Substances used to look like a genuine. Ie: Glass, plastic, etc.
  • Inclusions…Solid, gaseous, or liquid material of various types incorporated in a crystal during its formation and growth.
  • Intaglio…Incised carving; a sunken design, i.e.: Cameo
  • Intarsia…Mosaic inlay work using colored stones (and wood).
  • Ion…Electrically charged atom, radical or molecule.
  • Isomorphous …Minerals in which two or more elements can replace each other to any extent without notably changing the appearance of the crystal.
  • Isotropic…Materials in which the optical character is the same in all directions.
  • Labradorescence…Patchy or diffuse iridescence due to the interference of light by reflection from parallel inclusions. Example Labradorite.
  • Light…Radiant energy which gives the sensation of sight. Velocity is 186, 285 miles per second.
  • Litmus paper… Colored paper used to show whether a solution is acid or alkaline.
  • Lopolith. A large, lenticular, sunken mass of igneous rock whose surfaces are concordant with the enclosing rocks.
  • Luster…A reflective property of mineral surfaces.
  • Magma…Molten silica containing volatile substances in solution, present beneath the surface in certain areas of the earth's crust.
  • Malleable…Can be flattened by pounding, as in metals.
  • Mammillary… Rounded mineral surface
  • Massive…Minerals not bounded by crystal faces.
  • Metamorphism… (geological). Changes in rocks brought about by heat and pressure acting in the rocks just below the surface.
  • Meteorite…Solid object that comes from outer space and falls to earth.
  • Miaroles…Small cavities in granitic rocks created by volatile components.
  • Miller indices…Group of three digits used to designate crystal faces.
  • Mohs Scale…The relative scale of the hardness of minerals, from 1 to 10, the order of hardness with no significance to quantitative relationship.
  • Molecule…Two or more atoms in close relationship, The smallest quantity of an element or compound which is capable of independent existence.
  • Monochromatic Light…Light of one wavelength only.