In english, we often omit the article when speaking about construction or manufacturing material, like so: "This metal is so hard that you need diamond to carve letters in it.", implying you don't need an actual diamond, but maybe diamond-tipped tools. Another example is: "We'll need cement to build it." Can this be in general done in German (e.g. "Dieses Metall ist so hart, dass man Diamant braucht, um Buchstaben einzuritzen."), or how would similar formulations be translated?
The relevant term is Nullartikel. On the linked page you will find, that for materials and substances when talked about in general no article is required. In most cases an article would even spoil the sentence.