Adamant Ore is a fairly rare ore in Telicraft. It generates between levels 0 and 43. The world generator is set to try and generate 9 veins made out of 1 to 8 ore blocks per chunk.

Telinc's testing has proven that Adamant Ore often spawns near Diamonds. As a result of that, it is recommended that you look around when you find some.

Also, according to Thesupremedony - one of Telinc's friends, Adamant spawns near lava lakes, so take caution when mining!