Substances that can be hammered or rolled into sheets are called malleable.

Here's why:

* Malleability is a physical property of a material that allows it to deform under compressive stress without fracturing. This means the material can be shaped without breaking.

* Hammering and rolling are processes that apply compressive stress to a material, making them ideal for testing malleability.

Examples of malleable materials include:

* Metals: Gold, silver, copper, aluminum, and many more.

* Some alloys: Brass, bronze, etc.

Let me know if you have any other questions!