Dowsing/old

Copper

Appears as copper with 0 perception . Copper veins are usually quite long and narrow, no more then 5-10 coordinates wide and up to 100-200 coordinates long. The vein can run in any direction.

Iron

Appears as iron with 2 perception. Iron veins are usually quite long and narrow, no more then 5-10 coordinates wide and up to 100-200 coordinates long. The vein can run in any direction.

Tin

Appears as unknown with 2 perception. Usually appears at the intersection of iron and copper veins. While iron and copper veins are long and narrow, tin appears as a small blob as small as 25x25 coordinates in size.

Are you sure about the intersection thing? Got Iron/Copper/Iron and no tin -Orrin

I found a tin blob at an intersection of 2 iron veins -Mansku

Aluminum

Appears as unknown with 2 perception. While iron, copper, and tin are often found together, aluminum is usually found on it's own. With 2 perception you can use this to tell aluminum from tin by dowsing the surrounding area for iron or copper. -Not entirely true. Assuming that veins follow the same very basic idea of T4, 'rarer' veins are associated with iron/copper veins (possibly tin also, but that's irrelevant). As such you could have a copper vein meeting say, a silver vein.

Aluminum still dowses Unrecognized at 4 Per.

(tehm: I have copper near my Alum)

=== Titanium and Antimony === Spiral of Titanium with a small blob of Antimony in the middle. See map for dowsing detail:
Titanium/Antimony Dowsing Map