9 Photos
Kamacite
Chemical Formula	α-(Fe,Ni); Fe0+0.9Ni0.1
Species	Native Elements
Crystal System	Isometric
Mohs Scale	4
Specific Gravity	7.9
Color	Iron black, steel gray
Streak	gray
Luster	Metallic
Cleavage	Indistinct
Fracture	Hackly - Jagged, torn surfaces, (e.g. fractured metals).
Crystal Habit：Massive - uniformly indistinguishable crystals forming large masses

Kamacite is a variety of iron. It is an alloy of iron and nickel, usually in the proportions of 90:10 to 95:5 although impurities such as cobalt or carbon may be present. On the surface of Earth, it occurs naturally only in meteorites. It has a metallic luster, is gray and has no clear cleavage although the structure is isometric-hexoctahedral. Its density is around 8 g/cm3 and its hardness is 4 on the Mohs scale. It is also sometimes called balkeneisen.

The name was coined in 1861 and is derived from the Greek kamask (lath or beam). It is a major constituent of iron meteorites (octahedrite and hexahedrite types). In the octahedrites it is found in bands interleaving with taenite forming Widmanst?tten patterns. In hexahedrites, fine parallel lines called Neumann lines are often seen, which are evidence for structural deformation of adjacent kamacite plates due to shock from impacts.

At times kamacite can be found so closely intermixed with taenite that it is difficult to distinguish them visually, forming plessite. The largest documented kamacite crystal measured 92×54×23 cm.

See also: list of minerals