Large veins of adamantine are located in the second biome located on the map. http://i.imgur.com/wDIyBZ2.png You can move around the embark some and still get the adamantine from the biome, but this was the best spot I could find that also had magma at a high Z-level.


Z-Level 125: Surface (Sand, Fire Clay, Lots of Trees)
Z-Level 121-100: Limestone & Marble Layers
Z-Level 95: Magma Tubes
Z-Level 87 to -18: 10k+ adamantine

Other Ores:
140k Galena
29k Tetrahedrite
15k Malachite
12k Gold
9k Sphalerite
7k Silver
6k Cassitierite
4k Garnierite
2K Bismuthinite
600 Platinum

Other Stone:
13k Jet (For lightweight stone pots, etc)

The only downside for the map is no iron or coal for steel. But I figured I could always just trade for that or use goblinite, and with 10k adamantine, who cares about steel anyway?