The general term "Damascus" refers to metal with a visible grain patter, sometimes with a texture. Modern damascus is a lamination of folded steels selected with cosmetic qualities, with grinding and polishing specifically to expose the layers. True Damascus patterns are formed when carbon trace elements form visible swirls in the steel mix, that change the properties wihen work hardened (forged).
Pattern welded Damascus is made out of several types of steel and iron slices, which are then welded together to form a billet. The patterns vary depending on what the smith does to the billet. The billet is drawn out and folded until the desired number of layers are formed. The end result, if done well, bears a strong resemblance to the surface appearance of a true Damascus blade, though the internal structure is completely dissimilar.