The other types of items are socketed. These items use gems and skulls that you find throughout the game to give apparently normal items magical bonuses. You can find shields, weapons, and helms with open sockets, and when you also hold a gem or skull, you can place it in the item. The type and amount of the bonus varies according to what item you place in the socket, and the quality of the item. There are a multitude of gems, plus skulls.
Quality ranges from chips at the low end to perfect at the high end.
My only word of advice on using these is to plan ahead. Once you place a gem in a socket, it is there forever. If you play your cards well, the right combinations can make some truly powerful items. All in all, I have been very satisfied with shelling out 50 bucks for this game. Orcs versus Humans back in '94, I stood by their side and defended them every time my customers were let down when the release date was moved back yet another month.