What is the opposite of malleable?

Explanation:

Malleable refers to the quality of being susceptible to change, it can be molded. When we use this concept for materials, it means materials that can be pressured, hammered to change its shape, without cracking.

So, the opposite definition of malleable could be rigid, because this word refers to the lack of changing the form and shaped. When we talk about rigid objects, that means, if you pressured those objects, if you push them or hammer them, they will break before you can change their form.

An example of an object that is not malleable is the glass, you can change its form by pressuring it. However, if heat it, you will change its composition, and as a more liquid substance, you can change the form of the glass, but notice that you need to change its composition by adding heat.