Powdery, earthy habit.

 

An eight-sided crystal of the Isometric System.

 

Habit made up of small rounded grains.

 

Showing an internal play of colors or iridescence.

 

Not allowing the transmission of any light through a mineral.

 

In mining, underground passage excavated nearly horizontally, with one end open to the earth’s surface, usually used to service a mine. The adit end is the furthermost end from the surface, i.e., the location where miners work. The adit collar is the area where an adit opens to the surface and must be reinforced against any surface weakness.

 

A method of mining pillars in which no stump is left; the pockets driven are open on the gob side and the roof is supported by timber.

 

A natural aggregate of one or more minerals that can be mined and profitably sold under current conditions, or from which one or more minerals can be profitably extracted.

 

Mineralized mass whose characteristics have been determined and deemed to be commercially viable. The term "orebody" is used once the economic limits of the mineralized mass and its grade have been examined.

 

A polymorph of other minerals that share the same chemistry, but have different crystal structures. If positive identification between these minerals can not be made by field methods, then the specimen may simply be referred to as a potassium feldspar or K-spar. Plagioclase feldspars lack potassium, are light colored and are usually striated. The other k-spar minerals are sanidine, microcline and anorthoclase. Orthoclase is the more common of the k-spars.

 

Nearer to the shaft, and hence farther from the working face. Toward the mine entrance. The opposite of inby.