Whn a meteor land here and it's analyzed is the composition exactly the same as materials here on earth?

[What-The-F-Man]

Or have we ever found a metal or rock that does not exist at all on this planet?

[jomifl]

same basic stuff, different proportions of elements. nothing that hasn't been found here already. If there was it would be called meteoritium or similar.

[What-The-F-Man]

Cheers jomifil.

[jake-the-peg]

You tend to find relatively high quantities of Iridium.

There is also a high concentration of iridium in the worldwide K-T boundary (Between the Creatacious and Tertiary periods) which was the first evidence for the involvement of a meteor strike in the dinosaurs mass-extinction.

You do also get iridium as an imputity in platinum.