The following is my defenitions for Adamantine and it's raw metal, as you can see, the value's pretty hefty and it's pretty common considering the [ENVIRONMENT:ALL_STONE:VEIN:1000], however, I've had flying tentacle demons slaughter my dwarves more than once, and your traps don't hurt them.
[MATGLOSS_METAL:ADAMANTINE]
[NAME:adamantine][ADJ:adamantine][COLOR:3:3:1]
[VALUE:5000]
[SPEC_HEAT:7500]
[MELTING_POINT:25000]
[BOILING_POINT:50000]
[WEAPON][WEAPON_RANGED][AMMO][DIGGER][ARMOR][ANVIL][ANY_USE]
[WAFERS]
[DAMAGE_PERC:500]
[BLOCK_PERC:500]
[SOLID_DENSITY:50]
[DEEP]
[MATGLOSS_STONE:RAW_ADAMANTINE]
[NAME:raw adamantine][COLOR:3:7:1][TILE:156]
[ENVIRONMENT:ALL_STONE:VEIN:1000]
[ITEM_SYMBOL:'*']
[VALUE:1000]
[SPEC_HEAT:7500]
[MELTING_POINT:25000]
[BOILING_POINT:50000]
[SOLID_DENSITY:200]
[THREAD_METAL:ADAMANTINE:100]
[DEEP]