A mineral is a naturally occuring, homogeneous, solid with a crystalline atomic structure. Crystallinity implies that a mineral has a definite and limited range of composition, and that the composition is expressible as a chemical formula. Some definitions of minerals give them as inorganic materials, however both diamonds and graphite are considered minerals, and both are primarily comprised of carbon, which would make them organic. So this leads me, as an engineer, to believe that mineralogists do not have a good, precise definition of a mineral, but rather a loose definition. The definition above, is the most inclusive and would include all substances currently described as minerals. The key items that make something a mineral are occurring naturally, and the definite crystal structure, that is expressible as a chemical formula. Rocks that do not meet this criteria are referred to as amorphis - not having a definite structure or expressible as a chemical formula. Some elements that occur naturally and are minerals are arsenic, bismuth, platinum, gold, silver, copper, and sulphur.

THE DEFINITION OF ORGANIC: Organic chemistry is the study of those substances containing carbon in combination with hydrogen (H), and a few other non metals, namely oxygen (O), nitrogen (N), sulfur (S) and the halogens (F2, Cl2, Br2, and I2).

Stibnite is prismatic and can be highly modified, has a hardness of 2 mhos, and a specific gravity of 4.65. It is often vertically striated, bent or twisted, and can be in a radial aggregate, bladed, columnar, or granular. The stibnite in the top two photo's is vertically striated, and is from the Wuning Mine, Jangxi Province of China. The stibnite in the bottom photo is in a radial aggregate.

It has a metallic luster, is gray in color and streak. It can oxidize to black. Some stibnite can contain gold and silver. It is typically found in veins with quartz and various other antimony minerals, with galena, barite, cinnabar, sphalerite and gold.

Stibnite is a major source of metalic antimony, and is used in the manufacture of lead for batteries, rubber, paint medicines and other metallurgical applications.