A horizontal or a nearly horizontal underground passage, either natural or artificial.

 

Rock surrounding a mineral or precious gem in its natural state.

 

Showing a knee-like bend or bends.

 

The study of the chemical components of the earth's crust and mantle. Geochemistry is applied to mining exploration to detect sites that indicate abnormal concentrations either of the elements being sought or of their more readily detected associate elements. Depending on circumstance, geochemical exploration samples soils, rock, and lake and stream sediments.

 

Geological formations common to the United States (Indiana, the Keokuk area of Iowa and Kentucky), Brazil, and Mexico. Essentially rock bubbles with internal crystal formations, the exterior of a geode is generally limestone or a related rock, while the interior contains quartz crystals and/or chalcedony deposits. Other geodes are completely filled with crystal, being solid all the way though. These types of geodes are called nodules.

 

One who studies the constitution, structure, and history of the earth's crust, conducting research into the formation and dissolution of rock layers, analyzing fossil and mineral content of layers, and endeavoring to fix historical sequence of development by relating characteristics to known geological influences (historical geology).

 

Science devoted to the study of the structure and evolution of the earth's crust.

 

Study of the various physical properties of the earth and the composition and movement of its component layers of rock. Geophysics is applied to mining exploration to detect zones characterized by their physical properties such as magnetism, gravity or conductivity (electromagnetism).

 

A luster, slightly less bright than Adamantine.

 

Round bubbly masses that are less uniform than mammillary or botryoidal.

 

A very ductile and malleable, brilliant yellow precious metal that is resistant to air and water corrosion.