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).

Rutile is a major mineral source of the element titanium. Rutile is typically about 60% titanium and 40% oxygen. It can have some iron present, sometimes up to 10%. The rutile specimen in the photo does have about 5% iron in it. Rutile is one of the most common titanium minerals, occurring in gneiss, mica, schist, granite, limestone and dolomite. It is also associated with quartz, hematite and feldspar. As a secondary mineral, it is common in beach sand deposits, along with the other titanium mineral, ilmenite.

Rutile is brownish red and other shades, but not black. It has a hardness of 6.6, specific gravity of 4.18 to 5.2, a metalic luster and a pale brown streak. It's crystals are prismatic, vertically striated or furrowed. It fractures unevenly, to subconchoidal.

Major uses of this lightweight, high strength, non-corrosive metal are aerospace, automobiles, sports, and medicine. Still, its main use is in paint as a paint pigment. It replaced lead as the most common paint pigment used in the manufacture of paint. Other uses include a coating for tiles, and it is used to treat the air, both to preserve fruits and vegetables and to remove pollution.