About 27% of all known Meteorites.

Three main types and many sub-types:

Octahedrites:
The most common, they contain 7% to 15% nickel and show a clear Widmanstatten pattern when etched.

Ataxites:
They contain more than 15% Nickel and show no Widmanstatten pattern.

Hexahedrites:
They contain very little Nickel and may show some parallel lines, the Neumann lines when etched.