AQUA RAIN WATER FILTER REVIEWS

Origin
Iron meteorites have been linked to M-type asteroids since both types of objects have similar spectral characteristics in the visible and near-infrared wavelength regions. Iron meteorites are thought to be the fragments of the cores of larger ancient asteroids that have been shattered by impacts. The heat released from the radioactive decay of the short-lived nuclides 26Al and 60Fe is considered as a plausible cause for the melting and differentiation of their parent bodies in the early solar system.[4][5] The IIE chemical class may be a notable exception, in that they probably originate from the crust of S-type asteroid 6 Hebe.
Chemical and isotope analysis indicates that at least about 50 distinct parent bodies were involved. This implies that there were once at least this many large, differentiated, asteroids in the asteroid belt – many more than today.

Composition
The overwhelming bulk of these meteorites consists of the Fe,Ni-alloys kamacite and taenite. Minor minerals, when occurring, often form rounded nodules of troilite or graphite, surrounded by schreibersite and cohenite. Schreibersite and troilite also occur as plate shaped inclusions, which show up on cut surfaces as cm-long and mm-thick lamellae. The troilite plates are called Reichenbach lamellae.
The chemical composition is dominated by the elements Fe, Ni and Co, which make up more than 95%. Ni is always present; the concentration is nearly always higher than 5% and may be as high as about 25%.[7] A significant percentage of nickel can be used in the field to distinguish meteoritic irons from man-made products, which usually contain lower amounts of Ni, but it is not enough to prove the meteoritic origin (e.g. some US coins).

Use
The iron nickel alloy was used by several cultures for the manufacturing of tools and weapons. For example the Inuit used parts of the Cape York meteorite.[8][9][10] Fragments from Gibeon were used for centuries by Nama people. There are also reports of their use for manufacture of various items in Tibet (see Thokcha).
Today meteoritic iron is used in niche jewellery and knife production, but most of it is used for research, educational or collecting purposes.

Classification
Two classifications are in use: the classic structural classification and the newer chemical classification.

Structural classification
The older structural classification is based on the presence or absence of the Widmanstatten pattern, which can be assessed from the appearance of polished cross-sections that have been etched with acid. This is connected with the relative abundance of nickel to iron. The categories are:
Hexahedrites (H): low nickel, no Widmanstatten pattern, may present Neumann lines;
Octahedrites (O): average to high nickel, Widmanstatten patterns, most common class. They can be further divided up on the basis of the width of the kamacite lamellae from coarsest to finest.[1
Coarsest (Ogg): lamellae width > 3.3 mm
Coarse (Og): lamellae width 1.3-3.3 mm
Medium (Om): lamellae width 0.5-1.3 mm
Fine (Of): lamellae width 0.2-0.5 mm
Finest (Off): lamellae width < 0.2 mm
Plessitic (Opl): a transitional structure between octahedrites and ataxites[13]
Ataxites (D): very high nickel, no Widmanstatten pattern, rare.