Coin composition 0

[Iceman]

I have two specimen Icelandic 1940 2 kronur coins that are from the EX-King Norton mint collection graded by PCGS and as well as two one Krona specimens from the same mint. I was thinking of have them graded by NGC.   I have the one krona and two kronur in what appears to be in the yellowish brass alloy and the second set in a Tinish like alloy ...( A off metal) ....Now my question is will you or can someone be able to tell me what the off metal composition is and if so can it be noted on the NGC label..... as well as the mint collection it came from. 

[DWLange]

They both appear to be brass, but the second example is dull or toned on its obverse.

[Iceman]

51 minutes ago, DWLange said:

They both appear to be brass, but the second example is dull or toned on its obverse.

I assumed they are both a brass alloy but one appears to have more tin in the metal. Now I have seen about 5 to 6 others in both types and they also appear to have the yellow brass and the tinish brass There is no mistaking .them as being toned  Can they be analysed with out being damaged to determined the composition of the metal. 

[DWLange]

NGC will do that on request for a a fee of $75.